Mejora el clima organizacional
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Hola, ,
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--------------
Atte.: Daniel Rodríguez
Ciudad de México: (55) 5018 0565
WhatsApp: +52 33 1607 2089
Si no deseas recibir más correos, haz clic aquí para darte de baja.
Para remover su dirección de esta lista haga <a href="https://s1.arrobamail.com/unsuscribe.php?id=yiwtsrewisppuseup">click aquí</a>
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x e84cb860ac3ce67ec6ecc364433fd5b412c448bc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102634-cache-seventeen-becb@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e84cb860ac3ce67ec6ecc364433fd5b412c448bc Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Mon, 20 Oct 2025 22:53:26 +0200
Subject: [PATCH] mptcp: pm: in-kernel: C-flag: handle late ADD_ADDR
The special C-flag case expects the ADD_ADDR to be received when
switching to 'fully-established'. But for various reasons, the ADD_ADDR
could be sent after the "4th ACK", and the special case doesn't work.
On NIPA, the new test validating this special case for the C-flag failed
a few times, e.g.
102 default limits, server deny join id 0
syn rx [FAIL] got 0 JOIN[s] syn rx expected 2
Server ns stats
(...)
MPTcpExtAddAddrTx 1
MPTcpExtEchoAdd 1
Client ns stats
(...)
MPTcpExtAddAddr 1
MPTcpExtEchoAddTx 1
synack rx [FAIL] got 0 JOIN[s] synack rx expected 2
ack rx [FAIL] got 0 JOIN[s] ack rx expected 2
join Rx [FAIL] see above
syn tx [FAIL] got 0 JOIN[s] syn tx expected 2
join Tx [FAIL] see above
I had a suspicion about what the issue could be: the ADD_ADDR might have
been received after the switch to the 'fully-established' state. The
issue was not easy to reproduce. The packet capture shown that the
ADD_ADDR can indeed be sent with a delay, and the client would not try
to establish subflows to it as expected.
A simple fix is not to mark the endpoints as 'used' in the C-flag case,
when looking at creating subflows to the remote initial IP address and
port. In this case, there is no need to try.
Note: newly added fullmesh endpoints will still continue to be used as
expected, thanks to the conditions behind mptcp_pm_add_addr_c_flag_case.
Fixes: 4b1ff850e0c1 ("mptcp: pm: in-kernel: usable client side with C-flag")
Cc: stable(a)vger.kernel.org
Reviewed-by: Geliang Tang <geliang(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251020-net-mptcp-c-flag-late-add-addr-v1-1-82070…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index e0f44dc232aa..2ae95476dba3 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -370,6 +370,10 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
}
subflow:
+ /* No need to try establishing subflows to remote id0 if not allowed */
+ if (mptcp_pm_add_addr_c_flag_case(msk))
+ goto exit;
+
/* check if should create a new subflow */
while (msk->pm.local_addr_used < endp_subflow_max &&
msk->pm.extra_subflows < limit_extra_subflows) {
@@ -401,6 +405,8 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
__mptcp_subflow_connect(sk, &local, &addrs[i]);
spin_lock_bh(&msk->pm.lock);
}
+
+exit:
mptcp_pm_nl_check_work_pending(msk);
}
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 268eb6fb908bc82ce479e4dba9a2cad11f536c9c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102701-refinish-carrot-c75e@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 268eb6fb908bc82ce479e4dba9a2cad11f536c9c Mon Sep 17 00:00:00 2001
From: Xu Yang <xu.yang_2(a)nxp.com>
Date: Fri, 19 Sep 2025 14:25:34 +0800
Subject: [PATCH] dt-bindings: usb: dwc3-imx8mp: dma-range is required only for
imx8mp
Only i.MX8MP need dma-range property to let USB controller work properly.
Remove dma-range from required list and add limitation for imx8mp.
Fixes: d2a704e29711 ("dt-bindings: usb: dwc3-imx8mp: add imx8mp dwc3 glue bindings")
Cc: stable <stable(a)kernel.org>
Reviewed-by: Jun Li <jun.li(a)nxp.com>
Signed-off-by: Xu Yang <xu.yang_2(a)nxp.com>
Reviewed-by: Frank Li <Frank.Li(a)nxp.com>
Acked-by: Conor Dooley <conor.dooley(a)microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/Documentation/devicetree/bindings/usb/fsl,imx8mp-dwc3.yaml b/Documentation/devicetree/bindings/usb/fsl,imx8mp-dwc3.yaml
index baf130669c38..73e7a60a0060 100644
--- a/Documentation/devicetree/bindings/usb/fsl,imx8mp-dwc3.yaml
+++ b/Documentation/devicetree/bindings/usb/fsl,imx8mp-dwc3.yaml
@@ -89,13 +89,21 @@ required:
- reg
- "#address-cells"
- "#size-cells"
- - dma-ranges
- ranges
- clocks
- clock-names
- interrupts
- power-domains
+allOf:
+ - if:
+ properties:
+ compatible:
+ const: fsl,imx8mp-dwc3
+ then:
+ required:
+ - dma-ranges
+
additionalProperties: false
examples:
The driver_find_device_by_of_node() function returns a device with its
reference count incremented. driver_find_device_by_of_node() is an inline
wrapper that calls driver_find_device(), which calls get_device(dev) and
returns the found device with an incremented reference count.
Fix this by adding the missing put_device() call after the device
operations are completed.
Found via static analysis.
Fixes: 89c788bab1f0 ("ARM: tegra: Add SMMU enabler in AHB")
Cc: stable(a)vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com>
---
drivers/amba/tegra-ahb.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/amba/tegra-ahb.c b/drivers/amba/tegra-ahb.c
index c0e8b765522d..6c306d017b67 100644
--- a/drivers/amba/tegra-ahb.c
+++ b/drivers/amba/tegra-ahb.c
@@ -147,6 +147,7 @@ int tegra_ahb_enable_smmu(struct device_node *dn)
val = gizmo_readl(ahb, AHB_ARBITRATION_XBAR_CTRL);
val |= AHB_ARBITRATION_XBAR_CTRL_SMMU_INIT_DONE;
gizmo_writel(ahb, val, AHB_ARBITRATION_XBAR_CTRL);
+ put_device(dev);
return 0;
}
EXPORT_SYMBOL(tegra_ahb_enable_smmu);
--
2.39.5 (Apple Git-154)
Since commit 4959aebba8c0 ("virtio-net: use mtu size as buffer length
for big packets"), when guest gso is off, the allocated size for big
packets is not MAX_SKB_FRAGS * PAGE_SIZE anymore but depends on
negotiated MTU. The number of allocated frags for big packets is stored
in vi->big_packets_num_skbfrags.
Because the host announced buffer length can be malicious (e.g. the host
vhost_net driver's get_rx_bufs is modified to announce incorrect
length), we need a check in virtio_net receive path. Currently, the
check is not adapted to the new change which can lead to NULL page
pointer dereference in the below while loop when receiving length that
is larger than the allocated one.
This commit fixes the received length check corresponding to the new
change.
Fixes: 4959aebba8c0 ("virtio-net: use mtu size as buffer length for big packets")
Cc: stable(a)vger.kernel.org
Signed-off-by: Bui Quang Minh <minhquangbui99(a)gmail.com>
---
Changes in v5:
- Move the length check to receive_big
- Link to v4: https://lore.kernel.org/netdev/20251022160623.51191-1-minhquangbui99@gmail.…
Changes in v4:
- Remove unrelated changes, add more comments
- Link to v3: https://lore.kernel.org/netdev/20251021154534.53045-1-minhquangbui99@gmail.…
Changes in v3:
- Convert BUG_ON to WARN_ON_ONCE
- Link to v2: https://lore.kernel.org/netdev/20250708144206.95091-1-minhquangbui99@gmail.…
Changes in v2:
- Remove incorrect give_pages call
- Link to v1: https://lore.kernel.org/netdev/20250706141150.25344-1-minhquangbui99@gmail.…
---
drivers/net/virtio_net.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a757cbcab87f..2c3f544add5e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -910,17 +910,6 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
goto ok;
}
- /*
- * Verify that we can indeed put this data into a skb.
- * This is here to handle cases when the device erroneously
- * tries to receive more than is possible. This is usually
- * the case of a broken device.
- */
- if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
- net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
- dev_kfree_skb(skb);
- return NULL;
- }
BUG_ON(offset >= PAGE_SIZE);
while (len) {
unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
@@ -2107,9 +2096,19 @@ static struct sk_buff *receive_big(struct net_device *dev,
struct virtnet_rq_stats *stats)
{
struct page *page = buf;
- struct sk_buff *skb =
- page_to_skb(vi, rq, page, 0, len, PAGE_SIZE, 0);
+ struct sk_buff *skb;
+
+ /* Make sure that len does not exceed the allocated size in
+ * add_recvbuf_big.
+ */
+ if (unlikely(len > vi->big_packets_num_skbfrags * PAGE_SIZE)) {
+ pr_debug("%s: rx error: len %u exceeds allocate size %lu\n",
+ dev->name, len,
+ vi->big_packets_num_skbfrags * PAGE_SIZE);
+ goto err;
+ }
+ skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE, 0);
u64_stats_add(&stats->bytes, len - vi->hdr_len);
if (unlikely(!skb))
goto err;
--
2.43.0
Check for returned DMA addresses using specialized dma_mapping_error()
helper which is generally recommended for this purpose by
Documentation/core-api/dma-api.rst:
"In some circumstances dma_map_single(), ...
will fail to create a mapping. A driver can check for these errors
by testing the returned DMA address with dma_mapping_error()."
Found via static analysis and this is similar to commit fa0308134d26
("ALSA: memalloc: prefer dma_mapping_error() over explicit address checking")
Fixes: 58ac1b379979 ("ARM: PL011: Fix DMA support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com>
---
drivers/tty/serial/amba-pl011.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 22939841b1de..7f17d288c807 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -628,7 +628,7 @@ static int pl011_dma_tx_refill(struct uart_amba_port *uap)
dmatx->len = count;
dmatx->dma = dma_map_single(dma_dev->dev, dmatx->buf, count,
DMA_TO_DEVICE);
- if (dmatx->dma == DMA_MAPPING_ERROR) {
+ if (dma_mapping_error(dma_dev->dev, dmatx->dma)) {
uap->dmatx.queued = false;
dev_dbg(uap->port.dev, "unable to map TX DMA\n");
return -EBUSY;
--
2.39.5 (Apple Git-154)
Our implementation for BAR2 (lmembar) resize works at the xe_vram layer
and only releases that BAR before resizing. That is not always
sufficient. If the parent bridge needs to move, the BAR0 also needs to
be released, otherwise the resize fails. This is the case of not having
enough space allocated from the beginning.
Also, there's a BAR0 in the upstream port of the pcie switch in BMG
preventing the resize to propagate to the bridge as previously discussed
in https://lore.kernel.org/intel-xe/20250721173057.867829-1-uwu@icenowy.me/
and https://lore.kernel.org/intel-xe/wqukxnxni2dbpdhri3cbvlrzsefgdanesgskzmxi5s…
I'm bringing that commit from Ilpo here so this can be tested with the
xe changes and propagate to stable. Note that the use of a pci fixup is
not ideal, but without intrusive changes on resource fitting it's
possibly the best alternative. I also have confirmation from HW folks
that the BAR in the upstream port has no production use.
I have more cleanups on top on the xe side, but those conflict with some
refactors Ilpo is working on as prep for the resource fitting, so I will
wait things settle to submit again.
I propose to take this through the drm tree.
With this I could resize the lmembar on some problematic hosts and after
doing an SBR, with one caveat: the audio device also prevents the BAR
from moving and it needs to be manually removed before resizing. With
the PCI refactors and BAR fitting logic that Ilpo is working on, it's
expected that it won't be needed for a long time.
Signed-off-by: Lucas De Marchi <lucas.demarchi(a)intel.com>
---
Ilpo Järvinen (1):
PCI: Release BAR0 of an integrated bridge to allow GPU BAR resize
Lucas De Marchi (1):
drm/xe: Move rebar to be done earlier
drivers/gpu/drm/xe/xe_pci.c | 2 ++
drivers/gpu/drm/xe/xe_vram.c | 34 ++++++++++++++++++++++++++--------
drivers/gpu/drm/xe/xe_vram.h | 1 +
drivers/pci/quirks.c | 23 +++++++++++++++++++++++
4 files changed, 52 insertions(+), 8 deletions(-)
base-commit: 8031d70dbb4201841897de480cec1f9750d4a5dc
change-id: 20250917-xe-pci-rebar-2-c0fe2f04c879
Lucas De Marchi
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 5370c31e84b0e0999c7b5ff949f4e104def35584
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102624-direness-catalyze-d721@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5370c31e84b0e0999c7b5ff949f4e104def35584 Mon Sep 17 00:00:00 2001
From: Lad Prabhakar <prabhakar.mahadev-lad.rj(a)bp.renesas.com>
Date: Fri, 17 Oct 2025 16:18:29 +0100
Subject: [PATCH] net: ravb: Enforce descriptor type ordering
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Ensure the TX descriptor type fields are published in a safe order so the
DMA engine never begins processing a descriptor chain before all descriptor
fields are fully initialised.
For multi-descriptor transmits the driver writes DT_FEND into the last
descriptor and DT_FSTART into the first. The DMA engine begins processing
when it observes DT_FSTART. Move the dma_wmb() barrier so it executes
immediately after DT_FEND and immediately before writing DT_FSTART
(and before DT_FSINGLE in the single-descriptor case). This guarantees
that all prior CPU writes to the descriptor memory are visible to the
device before DT_FSTART is seen.
This avoids a situation where compiler/CPU reordering could publish
DT_FSTART ahead of DT_FEND or other descriptor fields, allowing the DMA to
start on a partially initialised chain and causing corrupted transmissions
or TX timeouts. Such a failure was observed on RZ/G2L with an RT kernel as
transmit queue timeouts and device resets.
Fixes: 2f45d1902acf ("ravb: minimize TX data copying")
Cc: stable(a)vger.kernel.org
Co-developed-by: Fabrizio Castro <fabrizio.castro.jz(a)renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz(a)renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj(a)bp.renesas.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas(a)ragnatech.se>
Link: https://patch.msgid.link/20251017151830.171062-4-prabhakar.mahadev-lad.rj@b…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 9d3bd65b85ff..044ee83c63bb 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2211,13 +2211,25 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
skb_tx_timestamp(skb);
}
- /* Descriptor type must be set after all the above writes */
- dma_wmb();
+
if (num_tx_desc > 1) {
desc->die_dt = DT_FEND;
desc--;
+ /* When using multi-descriptors, DT_FEND needs to get written
+ * before DT_FSTART, but the compiler may reorder the memory
+ * writes in an attempt to optimize the code.
+ * Use a dma_wmb() barrier to make sure DT_FEND and DT_FSTART
+ * are written exactly in the order shown in the code.
+ * This is particularly important for cases where the DMA engine
+ * is already running when we are running this code. If the DMA
+ * sees DT_FSTART without the corresponding DT_FEND it will enter
+ * an error condition.
+ */
+ dma_wmb();
desc->die_dt = DT_FSTART;
} else {
+ /* Descriptor type must be set after all the above writes */
+ dma_wmb();
desc->die_dt = DT_FSINGLE;
}
ravb_modify(ndev, TCCR, TCCR_TSRQ0 << q, TCCR_TSRQ0 << q);
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x c3496c052ac36ea98ec4f8e95ae6285a425a2457
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102628-overrun-runny-87fb@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From c3496c052ac36ea98ec4f8e95ae6285a425a2457 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Mon, 20 Oct 2025 22:53:29 +0200
Subject: [PATCH] selftests: mptcp: join: mark 'delete re-add signal' as
skipped if not supported
The call to 'continue_if' was missing: it properly marks a subtest as
'skipped' if the attached condition is not valid.
Without that, the test is wrongly marked as passed on older kernels.
Fixes: b5e2fb832f48 ("selftests: mptcp: add explicit test case for remove/readd")
Cc: stable(a)vger.kernel.org
Reviewed-by: Geliang Tang <geliang(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251020-net-mptcp-c-flag-late-add-addr-v1-4-82070…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index d98f8f8905b9..b2a8c51a3969 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -4040,7 +4040,7 @@ endpoint_tests()
# remove and re-add
if reset_with_events "delete re-add signal" &&
- mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+ continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=0
pm_nl_set_limits $ns1 0 3
pm_nl_set_limits $ns2 3 3
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 5370c31e84b0e0999c7b5ff949f4e104def35584
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102624-thirsty-otter-d285@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5370c31e84b0e0999c7b5ff949f4e104def35584 Mon Sep 17 00:00:00 2001
From: Lad Prabhakar <prabhakar.mahadev-lad.rj(a)bp.renesas.com>
Date: Fri, 17 Oct 2025 16:18:29 +0100
Subject: [PATCH] net: ravb: Enforce descriptor type ordering
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Ensure the TX descriptor type fields are published in a safe order so the
DMA engine never begins processing a descriptor chain before all descriptor
fields are fully initialised.
For multi-descriptor transmits the driver writes DT_FEND into the last
descriptor and DT_FSTART into the first. The DMA engine begins processing
when it observes DT_FSTART. Move the dma_wmb() barrier so it executes
immediately after DT_FEND and immediately before writing DT_FSTART
(and before DT_FSINGLE in the single-descriptor case). This guarantees
that all prior CPU writes to the descriptor memory are visible to the
device before DT_FSTART is seen.
This avoids a situation where compiler/CPU reordering could publish
DT_FSTART ahead of DT_FEND or other descriptor fields, allowing the DMA to
start on a partially initialised chain and causing corrupted transmissions
or TX timeouts. Such a failure was observed on RZ/G2L with an RT kernel as
transmit queue timeouts and device resets.
Fixes: 2f45d1902acf ("ravb: minimize TX data copying")
Cc: stable(a)vger.kernel.org
Co-developed-by: Fabrizio Castro <fabrizio.castro.jz(a)renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz(a)renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj(a)bp.renesas.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas(a)ragnatech.se>
Link: https://patch.msgid.link/20251017151830.171062-4-prabhakar.mahadev-lad.rj@b…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 9d3bd65b85ff..044ee83c63bb 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2211,13 +2211,25 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
skb_tx_timestamp(skb);
}
- /* Descriptor type must be set after all the above writes */
- dma_wmb();
+
if (num_tx_desc > 1) {
desc->die_dt = DT_FEND;
desc--;
+ /* When using multi-descriptors, DT_FEND needs to get written
+ * before DT_FSTART, but the compiler may reorder the memory
+ * writes in an attempt to optimize the code.
+ * Use a dma_wmb() barrier to make sure DT_FEND and DT_FSTART
+ * are written exactly in the order shown in the code.
+ * This is particularly important for cases where the DMA engine
+ * is already running when we are running this code. If the DMA
+ * sees DT_FSTART without the corresponding DT_FEND it will enter
+ * an error condition.
+ */
+ dma_wmb();
desc->die_dt = DT_FSTART;
} else {
+ /* Descriptor type must be set after all the above writes */
+ dma_wmb();
desc->die_dt = DT_FSINGLE;
}
ravb_modify(ndev, TCCR, TCCR_TSRQ0 << q, TCCR_TSRQ0 << q);
The function qcom_slim_ngd_notify_slaves() calls of_slim_get_device() which
internally uses device_find_child() to obtain a device reference.
According to the device_find_child() documentation,
the caller must drop the reference with put_device() after use.
Found via static analysis and this is similar to commit 4e65bda8273c
("ASoC: wcd934x: fix error handling in wcd934x_codec_parse_data()")
Fixes: 917809e2280b ("slimbus: ngd: Add qcom SLIMBus NGD driver")
Cc: stable(a)vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com>
---
drivers/slimbus/qcom-ngd-ctrl.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index 4fb66986cc22..cd40ab839c54 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -1241,6 +1241,7 @@ static void qcom_slim_ngd_notify_slaves(struct qcom_slim_ngd_ctrl *ctrl)
if (slim_get_logical_addr(sbdev))
dev_err(ctrl->dev, "Failed to get logical address\n");
+ put_device(&sbdev->dev);
}
}
--
2.39.5 (Apple Git-154)
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x c3496c052ac36ea98ec4f8e95ae6285a425a2457
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102627-tug-sabbath-3edb@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From c3496c052ac36ea98ec4f8e95ae6285a425a2457 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Mon, 20 Oct 2025 22:53:29 +0200
Subject: [PATCH] selftests: mptcp: join: mark 'delete re-add signal' as
skipped if not supported
The call to 'continue_if' was missing: it properly marks a subtest as
'skipped' if the attached condition is not valid.
Without that, the test is wrongly marked as passed on older kernels.
Fixes: b5e2fb832f48 ("selftests: mptcp: add explicit test case for remove/readd")
Cc: stable(a)vger.kernel.org
Reviewed-by: Geliang Tang <geliang(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251020-net-mptcp-c-flag-late-add-addr-v1-4-82070…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index d98f8f8905b9..b2a8c51a3969 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -4040,7 +4040,7 @@ endpoint_tests()
# remove and re-add
if reset_with_events "delete re-add signal" &&
- mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+ continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=0
pm_nl_set_limits $ns1 0 3
pm_nl_set_limits $ns2 3 3
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x c3496c052ac36ea98ec4f8e95ae6285a425a2457
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102627-enclosure-issue-a264@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From c3496c052ac36ea98ec4f8e95ae6285a425a2457 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Mon, 20 Oct 2025 22:53:29 +0200
Subject: [PATCH] selftests: mptcp: join: mark 'delete re-add signal' as
skipped if not supported
The call to 'continue_if' was missing: it properly marks a subtest as
'skipped' if the attached condition is not valid.
Without that, the test is wrongly marked as passed on older kernels.
Fixes: b5e2fb832f48 ("selftests: mptcp: add explicit test case for remove/readd")
Cc: stable(a)vger.kernel.org
Reviewed-by: Geliang Tang <geliang(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251020-net-mptcp-c-flag-late-add-addr-v1-4-82070…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index d98f8f8905b9..b2a8c51a3969 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -4040,7 +4040,7 @@ endpoint_tests()
# remove and re-add
if reset_with_events "delete re-add signal" &&
- mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+ continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=0
pm_nl_set_limits $ns1 0 3
pm_nl_set_limits $ns2 3 3
In the commit referenced by the Fixes tag, devm_clk_get_enabled() was
introduced to replace devm_clk_get() and clk_prepare_enable(). While
the clk_disable_unprepare() call in the error path was correctly
removed, the one in the remove function was overlooked, leading to a
double disable issue.
Remove the redundant clk_disable_unprepare() call from gsbi_remove()
to fix this issue. Since all resources are now managed by devres
and will be automatically released, the remove function serves no purpose
and can be deleted entirely.
Fixes: 489d7a8cc286 ("soc: qcom: use devm_clk_get_enabled() in gsbi_probe()")
Signed-off-by: Haotian Zhang <vulab(a)iscas.ac.cn>
---
drivers/soc/qcom/qcom_gsbi.c | 8 --------
1 file changed, 8 deletions(-)
diff --git a/drivers/soc/qcom/qcom_gsbi.c b/drivers/soc/qcom/qcom_gsbi.c
index 8f1158e0c631..a25d1de592f0 100644
--- a/drivers/soc/qcom/qcom_gsbi.c
+++ b/drivers/soc/qcom/qcom_gsbi.c
@@ -212,13 +212,6 @@ static int gsbi_probe(struct platform_device *pdev)
return of_platform_populate(node, NULL, NULL, &pdev->dev);
}
-static void gsbi_remove(struct platform_device *pdev)
-{
- struct gsbi_info *gsbi = platform_get_drvdata(pdev);
-
- clk_disable_unprepare(gsbi->hclk);
-}
-
static const struct of_device_id gsbi_dt_match[] = {
{ .compatible = "qcom,gsbi-v1.0.0", },
{ },
@@ -232,7 +225,6 @@ static struct platform_driver gsbi_driver = {
.of_match_table = gsbi_dt_match,
},
.probe = gsbi_probe,
- .remove = gsbi_remove,
};
module_platform_driver(gsbi_driver);
--
2.25.1
Hi all,
This series resolves two new Kconfig warnings that I see in my test
framework from an ARM configuration getting bumped to 6.17 and enabling
these configurations in the process.
---
Nathan Chancellor (2):
clk: qcom: Fix SM_VIDEOCC_6350 dependencies
clk: qcom: Fix dependencies of QCS_{DISP,GPU,VIDEO}CC_615
drivers/clk/qcom/Kconfig | 4 ++++
1 file changed, 4 insertions(+)
---
base-commit: 30bf3ec8cb6b2d2e2f8715388395cbd27cbe4fc9
change-id: 20250930-clk-qcom-kconfig-fixes-arm-3611dec03c3e
Best regards,
--
Nathan Chancellor <nathan(a)kernel.org>
Hello,
New build issue found on stable-rc/linux-5.10.y:
---
implicit declaration of function ‘of_get_cpu_hwid’; did you mean ‘of_get_cpu_node’? [-Werror=implicit-function-declaration] in arch/riscv/kernel/cpu.o (arch/riscv/kernel/cpu.c) [logspec:kbuild,kbuild.compiler.error]
---
- dashboard: https://d.kernelci.org/i/maestro:aa2fc1f4fdbcaf13e029f04263806fde636d74fd
- giturl: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
- commit HEAD: 7288ed51fe2777d083b6cb13bd2d18f368fa425d
Log excerpt:
=====================================================
arch/riscv/kernel/cpu.c:24:33: error: implicit declaration of function ‘of_get_cpu_hwid’; did you mean ‘of_get_cpu_node’? [-Werror=implicit-function-declaration]
24 | *hart = (unsigned long) of_get_cpu_hwid(node, 0);
| ^~~~~~~~~~~~~~~
| of_get_cpu_node
AR init/built-in.a
CC kernel/locking/mutex.o
CC arch/riscv/mm/fault.o
cc1: some warnings being treated as errors
=====================================================
# Builds where the incident occurred:
## defconfig on (riscv):
- compiler: gcc-12
- config: https://files.kernelci.org/kbuild-gcc-12-riscv-68ff66e51198e7d4c92ca056/.co…
- dashboard: https://d.kernelci.org/build/maestro:68ff66e51198e7d4c92ca056
#kernelci issue maestro:aa2fc1f4fdbcaf13e029f04263806fde636d74fd
Reported-by: kernelci.org bot <bot(a)kernelci.org>
--
This is an experimental report format. Please send feedback in!
Talk to us at kernelci(a)lists.linux.dev
Made with love by the KernelCI team - https://kernelci.org
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x a91c8096590bd7801a26454789f2992094fe36da
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102625-cringing-unstuck-790a@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a91c8096590bd7801a26454789f2992094fe36da Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <dev(a)lankhorst.se>
Date: Wed, 23 Jul 2025 16:24:16 +0200
Subject: [PATCH] devcoredump: Fix circular locking dependency with
devcd->mutex.
The original code causes a circular locking dependency found by lockdep.
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 Tainted: G S U
------------------------------------------------------
xe_fault_inject/5091 is trying to acquire lock:
ffff888156815688 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}, at: __flush_work+0x25d/0x660
but task is already holding lock:
ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&devcd->mutex){+.+.}-{3:3}:
mutex_lock_nested+0x4e/0xc0
devcd_data_write+0x27/0x90
sysfs_kf_bin_write+0x80/0xf0
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (kn->active#236){++++}-{0:0}:
kernfs_drain+0x1e2/0x200
__kernfs_remove+0xae/0x400
kernfs_remove_by_name_ns+0x5d/0xc0
remove_files+0x54/0x70
sysfs_remove_group+0x3d/0xa0
sysfs_remove_groups+0x2e/0x60
device_remove_attrs+0xc7/0x100
device_del+0x15d/0x3b0
devcd_del+0x19/0x30
process_one_work+0x22b/0x6f0
worker_thread+0x1e8/0x3d0
kthread+0x11c/0x250
ret_from_fork+0x26c/0x2e0
ret_from_fork_asm+0x1a/0x30
-> #0 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}:
__lock_acquire+0x1661/0x2860
lock_acquire+0xc4/0x2f0
__flush_work+0x27a/0x660
flush_delayed_work+0x5d/0xa0
dev_coredump_put+0x63/0xa0
xe_driver_devcoredump_fini+0x12/0x20 [xe]
devm_action_release+0x12/0x30
release_nodes+0x3a/0x120
devres_release_all+0x8a/0xd0
device_unbind_cleanup+0x12/0x80
device_release_driver_internal+0x23a/0x280
device_driver_detach+0x14/0x20
unbind_store+0xaf/0xc0
drv_attr_store+0x21/0x50
sysfs_kf_write+0x4a/0x80
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
entry_SYSCALL_64_after_hwframe+0x76/0x7e
other info that might help us debug this:
Chain exists of: (work_completion)(&(&devcd->del_wk)->work) --> kn->active#236 --> &devcd->mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&devcd->mutex);
lock(kn->active#236);
lock(&devcd->mutex);
lock((work_completion)(&(&devcd->del_wk)->work));
*** DEADLOCK ***
5 locks held by xe_fault_inject/5091:
#0: ffff8881129f9488 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x72/0xf0
#1: ffff88810c755078 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x123/0x220
#2: ffff8881054811a0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x55/0x280
#3: ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
#4: ffffffff8359e020 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x72/0x660
stack backtrace:
CPU: 14 UID: 0 PID: 5091 Comm: xe_fault_inject Tainted: G S U 6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 PREEMPT_{RT,(lazy)}
Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
Hardware name: Micro-Star International Co., Ltd. MS-7D25/PRO Z690-A DDR4(MS-7D25), BIOS 1.10 12/13/2021
Call Trace:
<TASK>
dump_stack_lvl+0x91/0xf0
dump_stack+0x10/0x20
print_circular_bug+0x285/0x360
check_noncircular+0x135/0x150
? register_lock_class+0x48/0x4a0
__lock_acquire+0x1661/0x2860
lock_acquire+0xc4/0x2f0
? __flush_work+0x25d/0x660
? mark_held_locks+0x46/0x90
? __flush_work+0x25d/0x660
__flush_work+0x27a/0x660
? __flush_work+0x25d/0x660
? trace_hardirqs_on+0x1e/0xd0
? __pfx_wq_barrier_func+0x10/0x10
flush_delayed_work+0x5d/0xa0
dev_coredump_put+0x63/0xa0
xe_driver_devcoredump_fini+0x12/0x20 [xe]
devm_action_release+0x12/0x30
release_nodes+0x3a/0x120
devres_release_all+0x8a/0xd0
device_unbind_cleanup+0x12/0x80
device_release_driver_internal+0x23a/0x280
? bus_find_device+0xa8/0xe0
device_driver_detach+0x14/0x20
unbind_store+0xaf/0xc0
drv_attr_store+0x21/0x50
sysfs_kf_write+0x4a/0x80
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
? __f_unlock_pos+0x15/0x20
? __x64_sys_getdents64+0x9b/0x130
? __pfx_filldir64+0x10/0x10
? do_syscall_64+0x1a2/0xb60
? clear_bhb_loop+0x30/0x80
? clear_bhb_loop+0x30/0x80
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x76e292edd574
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89
RSP: 002b:00007fffe247a828 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000076e292edd574
RDX: 000000000000000c RSI: 00006267f6306063 RDI: 000000000000000b
RBP: 000000000000000c R08: 000076e292fc4b20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00006267f6306063
R13: 000000000000000b R14: 00006267e6859c00 R15: 000076e29322a000
</TASK>
xe 0000:03:00.0: [drm] Xe device coredump has been deleted.
Fixes: 01daccf74832 ("devcoredump : Serialize devcd_del work")
Cc: Mukesh Ojha <quic_mojha(a)quicinc.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Johannes Berg <johannes(a)sipsolutions.net>
Cc: Rafael J. Wysocki <rafael(a)kernel.org>
Cc: Danilo Krummrich <dakr(a)kernel.org>
Cc: linux-kernel(a)vger.kernel.org
Cc: stable(a)vger.kernel.org # v6.1+
Signed-off-by: Maarten Lankhorst <dev(a)lankhorst.se>
Cc: Matthew Brost <matthew.brost(a)intel.com>
Acked-by: Mukesh Ojha <mukesh.ojha(a)oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250723142416.1020423-1-dev@lankhorst.se
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c
index 37faf6156d7c..55bdc7f5e59d 100644
--- a/drivers/base/devcoredump.c
+++ b/drivers/base/devcoredump.c
@@ -23,50 +23,46 @@ struct devcd_entry {
void *data;
size_t datalen;
/*
- * Here, mutex is required to serialize the calls to del_wk work between
- * user/kernel space which happens when devcd is added with device_add()
- * and that sends uevent to user space. User space reads the uevents,
- * and calls to devcd_data_write() which try to modify the work which is
- * not even initialized/queued from devcoredump.
+ * There are 2 races for which mutex is required.
*
+ * The first race is between device creation and userspace writing to
+ * schedule immediately destruction.
*
+ * This race is handled by arming the timer before device creation, but
+ * when device creation fails the timer still exists.
*
- * cpu0(X) cpu1(Y)
+ * To solve this, hold the mutex during device_add(), and set
+ * init_completed on success before releasing the mutex.
*
- * dev_coredump() uevent sent to user space
- * device_add() ======================> user space process Y reads the
- * uevents writes to devcd fd
- * which results into writes to
+ * That way the timer will never fire until device_add() is called,
+ * it will do nothing if init_completed is not set. The timer is also
+ * cancelled in that case.
*
- * devcd_data_write()
- * mod_delayed_work()
- * try_to_grab_pending()
- * timer_delete()
- * debug_assert_init()
- * INIT_DELAYED_WORK()
- * schedule_delayed_work()
- *
- *
- * Also, mutex alone would not be enough to avoid scheduling of
- * del_wk work after it get flush from a call to devcd_free()
- * mentioned as below.
- *
- * disabled_store()
- * devcd_free()
- * mutex_lock() devcd_data_write()
- * flush_delayed_work()
- * mutex_unlock()
- * mutex_lock()
- * mod_delayed_work()
- * mutex_unlock()
- * So, delete_work flag is required.
+ * The second race involves multiple parallel invocations of devcd_free(),
+ * add a deleted flag so only 1 can call the destructor.
*/
struct mutex mutex;
- bool delete_work;
+ bool init_completed, deleted;
struct module *owner;
ssize_t (*read)(char *buffer, loff_t offset, size_t count,
void *data, size_t datalen);
void (*free)(void *data);
+ /*
+ * If nothing interferes and device_add() was returns success,
+ * del_wk will destroy the device after the timer fires.
+ *
+ * Multiple userspace processes can interfere in the working of the timer:
+ * - Writing to the coredump will reschedule the timer to run immediately,
+ * if still armed.
+ *
+ * This is handled by using "if (cancel_delayed_work()) {
+ * schedule_delayed_work() }", to prevent re-arming after having
+ * been previously fired.
+ * - Writing to /sys/class/devcoredump/disabled will destroy the
+ * coredump synchronously.
+ * This is handled by using disable_delayed_work_sync(), and then
+ * checking if deleted flag is set with &devcd->mutex held.
+ */
struct delayed_work del_wk;
struct device *failing_dev;
};
@@ -95,14 +91,27 @@ static void devcd_dev_release(struct device *dev)
kfree(devcd);
}
+static void __devcd_del(struct devcd_entry *devcd)
+{
+ devcd->deleted = true;
+ device_del(&devcd->devcd_dev);
+ put_device(&devcd->devcd_dev);
+}
+
static void devcd_del(struct work_struct *wk)
{
struct devcd_entry *devcd;
+ bool init_completed;
devcd = container_of(wk, struct devcd_entry, del_wk.work);
- device_del(&devcd->devcd_dev);
- put_device(&devcd->devcd_dev);
+ /* devcd->mutex serializes against dev_coredumpm_timeout */
+ mutex_lock(&devcd->mutex);
+ init_completed = devcd->init_completed;
+ mutex_unlock(&devcd->mutex);
+
+ if (init_completed)
+ __devcd_del(devcd);
}
static ssize_t devcd_data_read(struct file *filp, struct kobject *kobj,
@@ -122,12 +131,12 @@ static ssize_t devcd_data_write(struct file *filp, struct kobject *kobj,
struct device *dev = kobj_to_dev(kobj);
struct devcd_entry *devcd = dev_to_devcd(dev);
- mutex_lock(&devcd->mutex);
- if (!devcd->delete_work) {
- devcd->delete_work = true;
- mod_delayed_work(system_wq, &devcd->del_wk, 0);
- }
- mutex_unlock(&devcd->mutex);
+ /*
+ * Although it's tempting to use mod_delayed work here,
+ * that will cause a reschedule if the timer already fired.
+ */
+ if (cancel_delayed_work(&devcd->del_wk))
+ schedule_delayed_work(&devcd->del_wk, 0);
return count;
}
@@ -151,11 +160,21 @@ static int devcd_free(struct device *dev, void *data)
{
struct devcd_entry *devcd = dev_to_devcd(dev);
+ /*
+ * To prevent a race with devcd_data_write(), disable work and
+ * complete manually instead.
+ *
+ * We cannot rely on the return value of
+ * disable_delayed_work_sync() here, because it might be in the
+ * middle of a cancel_delayed_work + schedule_delayed_work pair.
+ *
+ * devcd->mutex here guards against multiple parallel invocations
+ * of devcd_free().
+ */
+ disable_delayed_work_sync(&devcd->del_wk);
mutex_lock(&devcd->mutex);
- if (!devcd->delete_work)
- devcd->delete_work = true;
-
- flush_delayed_work(&devcd->del_wk);
+ if (!devcd->deleted)
+ __devcd_del(devcd);
mutex_unlock(&devcd->mutex);
return 0;
}
@@ -179,12 +198,10 @@ static ssize_t disabled_show(const struct class *class, const struct class_attri
* put_device() <- last reference
* error = fn(dev, data) devcd_dev_release()
* devcd_free(dev, data) kfree(devcd)
- * mutex_lock(&devcd->mutex);
*
*
* In the above diagram, it looks like disabled_store() would be racing with parallelly
- * running devcd_del() and result in memory abort while acquiring devcd->mutex which
- * is called after kfree of devcd memory after dropping its last reference with
+ * running devcd_del() and result in memory abort after dropping its last reference with
* put_device(). However, this will not happens as fn(dev, data) runs
* with its own reference to device via klist_node so it is not its last reference.
* so, above situation would not occur.
@@ -374,7 +391,7 @@ void dev_coredumpm_timeout(struct device *dev, struct module *owner,
devcd->read = read;
devcd->free = free;
devcd->failing_dev = get_device(dev);
- devcd->delete_work = false;
+ devcd->deleted = false;
mutex_init(&devcd->mutex);
device_initialize(&devcd->devcd_dev);
@@ -383,8 +400,14 @@ void dev_coredumpm_timeout(struct device *dev, struct module *owner,
atomic_inc_return(&devcd_count));
devcd->devcd_dev.class = &devcd_class;
- mutex_lock(&devcd->mutex);
dev_set_uevent_suppress(&devcd->devcd_dev, true);
+
+ /* devcd->mutex prevents devcd_del() completing until init finishes */
+ mutex_lock(&devcd->mutex);
+ devcd->init_completed = false;
+ INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
+ schedule_delayed_work(&devcd->del_wk, timeout);
+
if (device_add(&devcd->devcd_dev))
goto put_device;
@@ -401,13 +424,20 @@ void dev_coredumpm_timeout(struct device *dev, struct module *owner,
dev_set_uevent_suppress(&devcd->devcd_dev, false);
kobject_uevent(&devcd->devcd_dev.kobj, KOBJ_ADD);
- INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
- schedule_delayed_work(&devcd->del_wk, timeout);
+
+ /*
+ * Safe to run devcd_del() now that we are done with devcd_dev.
+ * Alternatively we could have taken a ref on devcd_dev before
+ * dropping the lock.
+ */
+ devcd->init_completed = true;
mutex_unlock(&devcd->mutex);
return;
put_device:
- put_device(&devcd->devcd_dev);
mutex_unlock(&devcd->mutex);
+ cancel_delayed_work_sync(&devcd->del_wk);
+ put_device(&devcd->devcd_dev);
+
put_module:
module_put(owner);
free:
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 630785bfbe12c3ee3ebccd8b530a98d632b7e39d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102617-untrimmed-ideally-b80b@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 630785bfbe12c3ee3ebccd8b530a98d632b7e39d Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong(a)kernel.org>
Date: Tue, 21 Oct 2025 11:30:12 -0700
Subject: [PATCH] xfs: always warn about deprecated mount options
The deprecation of the 'attr2' mount option in 6.18 wasn't entirely
successful because nobody noticed that the kernel never printed a
warning about attr2 being set in fstab if the only xfs filesystem is the
root fs; the initramfs mounts the root fs with no mount options; and the
init scripts only conveyed the fstab options by remounting the root fs.
Fix this by making it complain all the time.
Cc: stable(a)vger.kernel.org # v5.13
Fixes: 92cf7d36384b99 ("xfs: Skip repetitive warnings about mount options")
Signed-off-by: Darrick J. Wong <djwong(a)kernel.org>
Reviewed-by: Christoph Hellwig <hch(a)lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino(a)redhat.com>
Signed-off-by: Carlos Maiolino <cem(a)kernel.org>
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 9d51186b24dd..c53f2edf92e7 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1379,16 +1379,25 @@ suffix_kstrtoull(
static inline void
xfs_fs_warn_deprecated(
struct fs_context *fc,
- struct fs_parameter *param,
- uint64_t flag,
- bool value)
+ struct fs_parameter *param)
{
- /* Don't print the warning if reconfiguring and current mount point
- * already had the flag set
+ /*
+ * Always warn about someone passing in a deprecated mount option.
+ * Previously we wouldn't print the warning if we were reconfiguring
+ * and current mount point already had the flag set, but that was not
+ * the right thing to do.
+ *
+ * Many distributions mount the root filesystem with no options in the
+ * initramfs and rely on mount -a to remount the root fs with the
+ * options in fstab. However, the old behavior meant that there would
+ * never be a warning about deprecated mount options for the root fs in
+ * /etc/fstab. On a single-fs system, that means no warning at all.
+ *
+ * Compounding this problem are distribution scripts that copy
+ * /proc/mounts to fstab, which means that we can't remove mount
+ * options unless we're 100% sure they have only ever been advertised
+ * in /proc/mounts in response to explicitly provided mount options.
*/
- if ((fc->purpose & FS_CONTEXT_FOR_RECONFIGURE) &&
- !!(XFS_M(fc->root->d_sb)->m_features & flag) == value)
- return;
xfs_warn(fc->s_fs_info, "%s mount option is deprecated.", param->key);
}
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 5370c31e84b0e0999c7b5ff949f4e104def35584
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102623-footless-outcast-b793@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5370c31e84b0e0999c7b5ff949f4e104def35584 Mon Sep 17 00:00:00 2001
From: Lad Prabhakar <prabhakar.mahadev-lad.rj(a)bp.renesas.com>
Date: Fri, 17 Oct 2025 16:18:29 +0100
Subject: [PATCH] net: ravb: Enforce descriptor type ordering
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Ensure the TX descriptor type fields are published in a safe order so the
DMA engine never begins processing a descriptor chain before all descriptor
fields are fully initialised.
For multi-descriptor transmits the driver writes DT_FEND into the last
descriptor and DT_FSTART into the first. The DMA engine begins processing
when it observes DT_FSTART. Move the dma_wmb() barrier so it executes
immediately after DT_FEND and immediately before writing DT_FSTART
(and before DT_FSINGLE in the single-descriptor case). This guarantees
that all prior CPU writes to the descriptor memory are visible to the
device before DT_FSTART is seen.
This avoids a situation where compiler/CPU reordering could publish
DT_FSTART ahead of DT_FEND or other descriptor fields, allowing the DMA to
start on a partially initialised chain and causing corrupted transmissions
or TX timeouts. Such a failure was observed on RZ/G2L with an RT kernel as
transmit queue timeouts and device resets.
Fixes: 2f45d1902acf ("ravb: minimize TX data copying")
Cc: stable(a)vger.kernel.org
Co-developed-by: Fabrizio Castro <fabrizio.castro.jz(a)renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz(a)renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj(a)bp.renesas.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas(a)ragnatech.se>
Link: https://patch.msgid.link/20251017151830.171062-4-prabhakar.mahadev-lad.rj@b…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 9d3bd65b85ff..044ee83c63bb 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2211,13 +2211,25 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
skb_tx_timestamp(skb);
}
- /* Descriptor type must be set after all the above writes */
- dma_wmb();
+
if (num_tx_desc > 1) {
desc->die_dt = DT_FEND;
desc--;
+ /* When using multi-descriptors, DT_FEND needs to get written
+ * before DT_FSTART, but the compiler may reorder the memory
+ * writes in an attempt to optimize the code.
+ * Use a dma_wmb() barrier to make sure DT_FEND and DT_FSTART
+ * are written exactly in the order shown in the code.
+ * This is particularly important for cases where the DMA engine
+ * is already running when we are running this code. If the DMA
+ * sees DT_FSTART without the corresponding DT_FEND it will enter
+ * an error condition.
+ */
+ dma_wmb();
desc->die_dt = DT_FSTART;
} else {
+ /* Descriptor type must be set after all the above writes */
+ dma_wmb();
desc->die_dt = DT_FSINGLE;
}
ravb_modify(ndev, TCCR, TCCR_TSRQ0 << q, TCCR_TSRQ0 << q);
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x a91c8096590bd7801a26454789f2992094fe36da
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102624-aspect-stumble-aea9@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a91c8096590bd7801a26454789f2992094fe36da Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <dev(a)lankhorst.se>
Date: Wed, 23 Jul 2025 16:24:16 +0200
Subject: [PATCH] devcoredump: Fix circular locking dependency with
devcd->mutex.
The original code causes a circular locking dependency found by lockdep.
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 Tainted: G S U
------------------------------------------------------
xe_fault_inject/5091 is trying to acquire lock:
ffff888156815688 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}, at: __flush_work+0x25d/0x660
but task is already holding lock:
ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&devcd->mutex){+.+.}-{3:3}:
mutex_lock_nested+0x4e/0xc0
devcd_data_write+0x27/0x90
sysfs_kf_bin_write+0x80/0xf0
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (kn->active#236){++++}-{0:0}:
kernfs_drain+0x1e2/0x200
__kernfs_remove+0xae/0x400
kernfs_remove_by_name_ns+0x5d/0xc0
remove_files+0x54/0x70
sysfs_remove_group+0x3d/0xa0
sysfs_remove_groups+0x2e/0x60
device_remove_attrs+0xc7/0x100
device_del+0x15d/0x3b0
devcd_del+0x19/0x30
process_one_work+0x22b/0x6f0
worker_thread+0x1e8/0x3d0
kthread+0x11c/0x250
ret_from_fork+0x26c/0x2e0
ret_from_fork_asm+0x1a/0x30
-> #0 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}:
__lock_acquire+0x1661/0x2860
lock_acquire+0xc4/0x2f0
__flush_work+0x27a/0x660
flush_delayed_work+0x5d/0xa0
dev_coredump_put+0x63/0xa0
xe_driver_devcoredump_fini+0x12/0x20 [xe]
devm_action_release+0x12/0x30
release_nodes+0x3a/0x120
devres_release_all+0x8a/0xd0
device_unbind_cleanup+0x12/0x80
device_release_driver_internal+0x23a/0x280
device_driver_detach+0x14/0x20
unbind_store+0xaf/0xc0
drv_attr_store+0x21/0x50
sysfs_kf_write+0x4a/0x80
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
entry_SYSCALL_64_after_hwframe+0x76/0x7e
other info that might help us debug this:
Chain exists of: (work_completion)(&(&devcd->del_wk)->work) --> kn->active#236 --> &devcd->mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&devcd->mutex);
lock(kn->active#236);
lock(&devcd->mutex);
lock((work_completion)(&(&devcd->del_wk)->work));
*** DEADLOCK ***
5 locks held by xe_fault_inject/5091:
#0: ffff8881129f9488 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x72/0xf0
#1: ffff88810c755078 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x123/0x220
#2: ffff8881054811a0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x55/0x280
#3: ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
#4: ffffffff8359e020 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x72/0x660
stack backtrace:
CPU: 14 UID: 0 PID: 5091 Comm: xe_fault_inject Tainted: G S U 6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 PREEMPT_{RT,(lazy)}
Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
Hardware name: Micro-Star International Co., Ltd. MS-7D25/PRO Z690-A DDR4(MS-7D25), BIOS 1.10 12/13/2021
Call Trace:
<TASK>
dump_stack_lvl+0x91/0xf0
dump_stack+0x10/0x20
print_circular_bug+0x285/0x360
check_noncircular+0x135/0x150
? register_lock_class+0x48/0x4a0
__lock_acquire+0x1661/0x2860
lock_acquire+0xc4/0x2f0
? __flush_work+0x25d/0x660
? mark_held_locks+0x46/0x90
? __flush_work+0x25d/0x660
__flush_work+0x27a/0x660
? __flush_work+0x25d/0x660
? trace_hardirqs_on+0x1e/0xd0
? __pfx_wq_barrier_func+0x10/0x10
flush_delayed_work+0x5d/0xa0
dev_coredump_put+0x63/0xa0
xe_driver_devcoredump_fini+0x12/0x20 [xe]
devm_action_release+0x12/0x30
release_nodes+0x3a/0x120
devres_release_all+0x8a/0xd0
device_unbind_cleanup+0x12/0x80
device_release_driver_internal+0x23a/0x280
? bus_find_device+0xa8/0xe0
device_driver_detach+0x14/0x20
unbind_store+0xaf/0xc0
drv_attr_store+0x21/0x50
sysfs_kf_write+0x4a/0x80
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
? __f_unlock_pos+0x15/0x20
? __x64_sys_getdents64+0x9b/0x130
? __pfx_filldir64+0x10/0x10
? do_syscall_64+0x1a2/0xb60
? clear_bhb_loop+0x30/0x80
? clear_bhb_loop+0x30/0x80
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x76e292edd574
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89
RSP: 002b:00007fffe247a828 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000076e292edd574
RDX: 000000000000000c RSI: 00006267f6306063 RDI: 000000000000000b
RBP: 000000000000000c R08: 000076e292fc4b20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00006267f6306063
R13: 000000000000000b R14: 00006267e6859c00 R15: 000076e29322a000
</TASK>
xe 0000:03:00.0: [drm] Xe device coredump has been deleted.
Fixes: 01daccf74832 ("devcoredump : Serialize devcd_del work")
Cc: Mukesh Ojha <quic_mojha(a)quicinc.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Johannes Berg <johannes(a)sipsolutions.net>
Cc: Rafael J. Wysocki <rafael(a)kernel.org>
Cc: Danilo Krummrich <dakr(a)kernel.org>
Cc: linux-kernel(a)vger.kernel.org
Cc: stable(a)vger.kernel.org # v6.1+
Signed-off-by: Maarten Lankhorst <dev(a)lankhorst.se>
Cc: Matthew Brost <matthew.brost(a)intel.com>
Acked-by: Mukesh Ojha <mukesh.ojha(a)oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250723142416.1020423-1-dev@lankhorst.se
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c
index 37faf6156d7c..55bdc7f5e59d 100644
--- a/drivers/base/devcoredump.c
+++ b/drivers/base/devcoredump.c
@@ -23,50 +23,46 @@ struct devcd_entry {
void *data;
size_t datalen;
/*
- * Here, mutex is required to serialize the calls to del_wk work between
- * user/kernel space which happens when devcd is added with device_add()
- * and that sends uevent to user space. User space reads the uevents,
- * and calls to devcd_data_write() which try to modify the work which is
- * not even initialized/queued from devcoredump.
+ * There are 2 races for which mutex is required.
*
+ * The first race is between device creation and userspace writing to
+ * schedule immediately destruction.
*
+ * This race is handled by arming the timer before device creation, but
+ * when device creation fails the timer still exists.
*
- * cpu0(X) cpu1(Y)
+ * To solve this, hold the mutex during device_add(), and set
+ * init_completed on success before releasing the mutex.
*
- * dev_coredump() uevent sent to user space
- * device_add() ======================> user space process Y reads the
- * uevents writes to devcd fd
- * which results into writes to
+ * That way the timer will never fire until device_add() is called,
+ * it will do nothing if init_completed is not set. The timer is also
+ * cancelled in that case.
*
- * devcd_data_write()
- * mod_delayed_work()
- * try_to_grab_pending()
- * timer_delete()
- * debug_assert_init()
- * INIT_DELAYED_WORK()
- * schedule_delayed_work()
- *
- *
- * Also, mutex alone would not be enough to avoid scheduling of
- * del_wk work after it get flush from a call to devcd_free()
- * mentioned as below.
- *
- * disabled_store()
- * devcd_free()
- * mutex_lock() devcd_data_write()
- * flush_delayed_work()
- * mutex_unlock()
- * mutex_lock()
- * mod_delayed_work()
- * mutex_unlock()
- * So, delete_work flag is required.
+ * The second race involves multiple parallel invocations of devcd_free(),
+ * add a deleted flag so only 1 can call the destructor.
*/
struct mutex mutex;
- bool delete_work;
+ bool init_completed, deleted;
struct module *owner;
ssize_t (*read)(char *buffer, loff_t offset, size_t count,
void *data, size_t datalen);
void (*free)(void *data);
+ /*
+ * If nothing interferes and device_add() was returns success,
+ * del_wk will destroy the device after the timer fires.
+ *
+ * Multiple userspace processes can interfere in the working of the timer:
+ * - Writing to the coredump will reschedule the timer to run immediately,
+ * if still armed.
+ *
+ * This is handled by using "if (cancel_delayed_work()) {
+ * schedule_delayed_work() }", to prevent re-arming after having
+ * been previously fired.
+ * - Writing to /sys/class/devcoredump/disabled will destroy the
+ * coredump synchronously.
+ * This is handled by using disable_delayed_work_sync(), and then
+ * checking if deleted flag is set with &devcd->mutex held.
+ */
struct delayed_work del_wk;
struct device *failing_dev;
};
@@ -95,14 +91,27 @@ static void devcd_dev_release(struct device *dev)
kfree(devcd);
}
+static void __devcd_del(struct devcd_entry *devcd)
+{
+ devcd->deleted = true;
+ device_del(&devcd->devcd_dev);
+ put_device(&devcd->devcd_dev);
+}
+
static void devcd_del(struct work_struct *wk)
{
struct devcd_entry *devcd;
+ bool init_completed;
devcd = container_of(wk, struct devcd_entry, del_wk.work);
- device_del(&devcd->devcd_dev);
- put_device(&devcd->devcd_dev);
+ /* devcd->mutex serializes against dev_coredumpm_timeout */
+ mutex_lock(&devcd->mutex);
+ init_completed = devcd->init_completed;
+ mutex_unlock(&devcd->mutex);
+
+ if (init_completed)
+ __devcd_del(devcd);
}
static ssize_t devcd_data_read(struct file *filp, struct kobject *kobj,
@@ -122,12 +131,12 @@ static ssize_t devcd_data_write(struct file *filp, struct kobject *kobj,
struct device *dev = kobj_to_dev(kobj);
struct devcd_entry *devcd = dev_to_devcd(dev);
- mutex_lock(&devcd->mutex);
- if (!devcd->delete_work) {
- devcd->delete_work = true;
- mod_delayed_work(system_wq, &devcd->del_wk, 0);
- }
- mutex_unlock(&devcd->mutex);
+ /*
+ * Although it's tempting to use mod_delayed work here,
+ * that will cause a reschedule if the timer already fired.
+ */
+ if (cancel_delayed_work(&devcd->del_wk))
+ schedule_delayed_work(&devcd->del_wk, 0);
return count;
}
@@ -151,11 +160,21 @@ static int devcd_free(struct device *dev, void *data)
{
struct devcd_entry *devcd = dev_to_devcd(dev);
+ /*
+ * To prevent a race with devcd_data_write(), disable work and
+ * complete manually instead.
+ *
+ * We cannot rely on the return value of
+ * disable_delayed_work_sync() here, because it might be in the
+ * middle of a cancel_delayed_work + schedule_delayed_work pair.
+ *
+ * devcd->mutex here guards against multiple parallel invocations
+ * of devcd_free().
+ */
+ disable_delayed_work_sync(&devcd->del_wk);
mutex_lock(&devcd->mutex);
- if (!devcd->delete_work)
- devcd->delete_work = true;
-
- flush_delayed_work(&devcd->del_wk);
+ if (!devcd->deleted)
+ __devcd_del(devcd);
mutex_unlock(&devcd->mutex);
return 0;
}
@@ -179,12 +198,10 @@ static ssize_t disabled_show(const struct class *class, const struct class_attri
* put_device() <- last reference
* error = fn(dev, data) devcd_dev_release()
* devcd_free(dev, data) kfree(devcd)
- * mutex_lock(&devcd->mutex);
*
*
* In the above diagram, it looks like disabled_store() would be racing with parallelly
- * running devcd_del() and result in memory abort while acquiring devcd->mutex which
- * is called after kfree of devcd memory after dropping its last reference with
+ * running devcd_del() and result in memory abort after dropping its last reference with
* put_device(). However, this will not happens as fn(dev, data) runs
* with its own reference to device via klist_node so it is not its last reference.
* so, above situation would not occur.
@@ -374,7 +391,7 @@ void dev_coredumpm_timeout(struct device *dev, struct module *owner,
devcd->read = read;
devcd->free = free;
devcd->failing_dev = get_device(dev);
- devcd->delete_work = false;
+ devcd->deleted = false;
mutex_init(&devcd->mutex);
device_initialize(&devcd->devcd_dev);
@@ -383,8 +400,14 @@ void dev_coredumpm_timeout(struct device *dev, struct module *owner,
atomic_inc_return(&devcd_count));
devcd->devcd_dev.class = &devcd_class;
- mutex_lock(&devcd->mutex);
dev_set_uevent_suppress(&devcd->devcd_dev, true);
+
+ /* devcd->mutex prevents devcd_del() completing until init finishes */
+ mutex_lock(&devcd->mutex);
+ devcd->init_completed = false;
+ INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
+ schedule_delayed_work(&devcd->del_wk, timeout);
+
if (device_add(&devcd->devcd_dev))
goto put_device;
@@ -401,13 +424,20 @@ void dev_coredumpm_timeout(struct device *dev, struct module *owner,
dev_set_uevent_suppress(&devcd->devcd_dev, false);
kobject_uevent(&devcd->devcd_dev.kobj, KOBJ_ADD);
- INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
- schedule_delayed_work(&devcd->del_wk, timeout);
+
+ /*
+ * Safe to run devcd_del() now that we are done with devcd_dev.
+ * Alternatively we could have taken a ref on devcd_dev before
+ * dropping the lock.
+ */
+ devcd->init_completed = true;
mutex_unlock(&devcd->mutex);
return;
put_device:
- put_device(&devcd->devcd_dev);
mutex_unlock(&devcd->mutex);
+ cancel_delayed_work_sync(&devcd->del_wk);
+ put_device(&devcd->devcd_dev);
+
put_module:
module_put(owner);
free: