From: Miri Korenblit <miriam.rachel.korenblit(a)intel.com>
[ Upstream commit d7a54d02db41f72f0581a3c77c75b0993ed3f6e2 ]
This is currently not initialized for a virtual monitor, leading to a
NULL pointer dereference when - for example - iterating over all the
keys of all the vifs.
Reviewed-by: Johannes Berg <johannes.berg(a)intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit(a)intel.com>
Link: https://patch.msgid.link/20250709233400.8dcefe578497.I4c90a00ae3256520e0631…
Signed-off-by: Johannes Berg <johannes.berg(a)intel.com>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
LLM Generated explanations, may be completely bogus:
Based on my analysis of the commit and the code changes, here is my
assessment:
**YES**
This commit should be backported to stable kernel trees for the
following reasons:
1. **Critical NULL Pointer Dereference Fix**: The commit fixes a NULL
pointer dereference that occurs when iterating over the key_list of
virtual monitor interfaces. This is a crash-inducing bug that affects
system stability.
2. **Clear Bug with Simple Fix**: The issue is straightforward - the
`key_list` was not initialized for virtual monitor interfaces created
via `ieee80211_add_virtual_monitor()`. The fix is minimal and
contained - it simply moves the `INIT_LIST_HEAD(&sdata->key_list)`
initialization from `ieee80211_if_add()` into
`ieee80211_sdata_init()`, ensuring all sdata structures have their
key_list properly initialized.
3. **Real-World Impact**: The bug can be triggered when any code
iterates over all interfaces and their keys. Looking at the code,
functions like `ieee80211_iter_keys()` and
`ieee80211_iter_keys_rcu()` iterate through all interfaces when
called without a specific vif parameter:
```c
list_for_each_entry(sdata, &local->interfaces, list)
list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
```
This would cause a NULL pointer dereference when it encounters a
virtual monitor interface.
4. **Minimal Risk**: The change is extremely low risk - it only adds
initialization of a list head that should have been initialized all
along. There are no architectural changes or feature additions.
5. **Follows Stable Rules**: This perfectly fits the stable kernel
criteria:
- Fixes a real bug (NULL pointer dereference/crash)
- Small and contained change (2 lines moved)
- Obviously correct fix
- No new features or behaviors introduced
The commit is similar in nature to commit #5 in the reference list which
was marked as suitable for backporting - both fix NULL pointer
dereferences in the wifi/mac80211 subsystem with minimal, targeted
changes.
net/mac80211/iface.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 209d6ffa8e426..adfdc14bd91ac 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1121,6 +1121,8 @@ static void ieee80211_sdata_init(struct ieee80211_local *local,
{
sdata->local = local;
+ INIT_LIST_HEAD(&sdata->key_list);
+
/*
* Initialize the default link, so we can use link_id 0 for non-MLD,
* and that continues to work for non-MLD-aware drivers that use just
@@ -2162,8 +2164,6 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
ieee80211_init_frag_cache(&sdata->frags);
- INIT_LIST_HEAD(&sdata->key_list);
-
wiphy_delayed_work_init(&sdata->dec_tailroom_needed_wk,
ieee80211_delayed_tailroom_dec);
--
2.39.5
From: Miri Korenblit <miriam.rachel.korenblit(a)intel.com>
[ Upstream commit d7a54d02db41f72f0581a3c77c75b0993ed3f6e2 ]
This is currently not initialized for a virtual monitor, leading to a
NULL pointer dereference when - for example - iterating over all the
keys of all the vifs.
Reviewed-by: Johannes Berg <johannes.berg(a)intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit(a)intel.com>
Link: https://patch.msgid.link/20250709233400.8dcefe578497.I4c90a00ae3256520e0631…
Signed-off-by: Johannes Berg <johannes.berg(a)intel.com>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
LLM Generated explanations, may be completely bogus:
Based on my analysis of the commit and the code changes, here is my
assessment:
**YES**
This commit should be backported to stable kernel trees for the
following reasons:
1. **Critical NULL Pointer Dereference Fix**: The commit fixes a NULL
pointer dereference that occurs when iterating over the key_list of
virtual monitor interfaces. This is a crash-inducing bug that affects
system stability.
2. **Clear Bug with Simple Fix**: The issue is straightforward - the
`key_list` was not initialized for virtual monitor interfaces created
via `ieee80211_add_virtual_monitor()`. The fix is minimal and
contained - it simply moves the `INIT_LIST_HEAD(&sdata->key_list)`
initialization from `ieee80211_if_add()` into
`ieee80211_sdata_init()`, ensuring all sdata structures have their
key_list properly initialized.
3. **Real-World Impact**: The bug can be triggered when any code
iterates over all interfaces and their keys. Looking at the code,
functions like `ieee80211_iter_keys()` and
`ieee80211_iter_keys_rcu()` iterate through all interfaces when
called without a specific vif parameter:
```c
list_for_each_entry(sdata, &local->interfaces, list)
list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
```
This would cause a NULL pointer dereference when it encounters a
virtual monitor interface.
4. **Minimal Risk**: The change is extremely low risk - it only adds
initialization of a list head that should have been initialized all
along. There are no architectural changes or feature additions.
5. **Follows Stable Rules**: This perfectly fits the stable kernel
criteria:
- Fixes a real bug (NULL pointer dereference/crash)
- Small and contained change (2 lines moved)
- Obviously correct fix
- No new features or behaviors introduced
The commit is similar in nature to commit #5 in the reference list which
was marked as suitable for backporting - both fix NULL pointer
dereferences in the wifi/mac80211 subsystem with minimal, targeted
changes.
net/mac80211/iface.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 7d93e5aa595b2..0485a78eda366 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1117,6 +1117,8 @@ static void ieee80211_sdata_init(struct ieee80211_local *local,
{
sdata->local = local;
+ INIT_LIST_HEAD(&sdata->key_list);
+
/*
* Initialize the default link, so we can use link_id 0 for non-MLD,
* and that continues to work for non-MLD-aware drivers that use just
@@ -2177,8 +2179,6 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
ieee80211_init_frag_cache(&sdata->frags);
- INIT_LIST_HEAD(&sdata->key_list);
-
wiphy_delayed_work_init(&sdata->dec_tailroom_needed_wk,
ieee80211_delayed_tailroom_dec);
--
2.39.5
Commit e7607f7d6d81 ("ARM: 9443/1: Require linker to support KEEP within
OVERLAY for DCE") accidentally broke the binutils version restriction
that was added in commit 0d437918fb64 ("ARM: 9414/1: Fix build issue
with LD_DEAD_CODE_DATA_ELIMINATION"), reintroducing the segmentation
fault addressed by that workaround.
Restore the binutils version dependency by using
CONFIG_LD_CAN_USE_KEEP_IN_OVERLAY as an additional condition to ensure
that CONFIG_HAVE_LD_DEAD_CODE_DATA_ELIMINATION is only enabled with
binutils >= 2.36 and ld.lld >= 21.0.0.
Cc: stable(a)vger.kernel.org
Fixes: e7607f7d6d81 ("ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE")
Reported-by: Rob Landley <rob(a)landley.net>
Closes: https://lore.kernel.org/6739da7d-e555-407a-b5cb-e5681da71056@landley.net/
Tested-by: Rob Landley <rob(a)landley.net>
Signed-off-by: Nathan Chancellor <nathan(a)kernel.org>
---
arch/arm/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3072731fe09c..962451e54fdd 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -121,7 +121,7 @@ config ARM
select HAVE_KERNEL_XZ
select HAVE_KPROBES if !XIP_KERNEL && !CPU_ENDIAN_BE32 && !CPU_V7M
select HAVE_KRETPROBES if HAVE_KPROBES
- select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if (LD_VERSION >= 23600 || LD_CAN_USE_KEEP_IN_OVERLAY)
+ select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if (LD_VERSION >= 23600 || LD_IS_LLD) && LD_CAN_USE_KEEP_IN_OVERLAY
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_OPTPROBES if !THUMB2_KERNEL
---
base-commit: d7b8f8e20813f0179d8ef519541a3527e7661d3a
change-id: 20250707-arm-fix-dce-older-binutils-87a5a4b829d9
Best regards,
--
Nathan Chancellor <nathan(a)kernel.org>
Hello,
with kernel v6.16-rc5-121-gbc9ff192a6c9 I see this:
cat /sys/devices/system/cpu/vulnerabilities/tsa
Mitigation: Clear CPU buffers
dmesg | grep micro
[ 1.479203] microcode: Current revision: 0x0a20102e
[ 1.479206] microcode: Updated early from: 0x0a201016
So, this works.
but same machine with 6.6.97:
dmesg | grep micro
[ 0.451496] Transient Scheduler Attacks: Vulnerable: Clear CPU buffers
attempted, no microcode
[ 1.077149] microcode: Current revision: 0x0a20102e
[ 1.077152] microcode: Updated early from: 0x0a201016
so:
cat /sys/devices/system/cpu/vulnerabilities/tsa
Vulnerable: Clear CPU buffers attempted, no microcode
but it is switched on:
zcat /proc/config.gz | grep TSA
CONFIG_MITIGATION_TSA=y
And other stuff which need microcode works:
cat /sys/devices/system/cpu/vulnerabilities/spec_rstack_overflow
Mitigation: Safe RET
without microcode you wwould see:
Vulnerable: Safe RET, no microcode
6.12.37 broken too
6.15.6 works
v6.16-rc5-121-gbc9ff192a6c9 works
This is a:
processor : 11
vendor_id : AuthenticAMD
cpu family : 25
model : 33
model name : AMD Ryzen 5 5600X 6-Core Processor
stepping : 0
microcode : 0xa20102e
Is something missing in 6.6.y and 6.12.y?
Thomas
(already submitted @ Fedora; advised to post here to upstream as well)
-------- Forwarded Message --------
Subject: regression in 6.15.5: KVM guest launch FAILSs with missing CPU feature error (sbpb, ibpb-brtype)
Date: Sun, 13 Jul 2025 17:37:57 -0400
From: pgnd <pgnd(a)dev-mail.net>
Reply-To: pgnd(a)dev-mail.net
To: kernel(a)lists.fedoraproject.org
i'm seeing a regression on Fedora 42 kernel 6.15.4 -> 6.15.5 on AMD Ryzen 5 5600G host (x86_64)
kvm guests that launch ok under kernels 6.15.[3,4] fail with the following error when attempting to autostart under 6.15.5:
internal error: Failed to autostart VM: operation failed: guest CPU doesn't match specification: missing features: sbpb,ibpb-brtype
no changes made to libvirt, qemu, or VM defs between kernel versions.
re-booting to old kernel versions restores expected behavior.
maybe related (?) to recent changes in AMD CPU feature exposure / mitigation handling in kernel 6.15.5?
i've opened a bug:
https://bugzilla.redhat.com/show_bug.cgi?id=2379784