The patch titled
Subject: mm/kasan: fix incorrect unpoisoning in vrealloc for KASAN
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-kasan-fix-incorrect-unpoisoning-in-vrealloc-for-kasan.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Jiayuan Chen <jiayuan.chen(a)linux.dev>
Subject: mm/kasan: fix incorrect unpoisoning in vrealloc for KASAN
Date: Fri, 28 Nov 2025 19:15:14 +0800
Syzkaller reported a memory out-of-bounds bug [1]. This patch fixes two
issues:
1. In vrealloc, we were missing the KASAN_VMALLOC_VM_ALLOC flag when
unpoisoning the extended region. This flag is required to correctly
associate the allocation with KASAN's vmalloc tracking.
Note: In contrast, vzalloc (via __vmalloc_node_range_noprof) explicitly
sets KASAN_VMALLOC_VM_ALLOC and calls kasan_unpoison_vmalloc() with it.
vrealloc must behave consistently ��� especially when reusing existing
vmalloc regions ��� to ensure KASAN can track allocations correctly.
2. When vrealloc reuses an existing vmalloc region (without allocating new
pages), KASAN previously generated a new tag, which broke tag-based
memory access tracking. We now add a 'reuse_tag' parameter to
__kasan_unpoison_vmalloc() to preserve the original tag in such cases.
A new helper kasan_unpoison_vralloc() is introduced to handle this reuse
scenario, ensuring consistent tag behavior during reallocation.
Link: https://lkml.kernel.org/r/20251128111516.244497-1-jiayuan.chen@linux.dev
Link: https://syzkaller.appspot.com/bug?extid=997752115a851cb0cf36 [1]
Fixes: a0309faf1cb0 ("mm: vmalloc: support more granular vrealloc() sizing")
Signed-off-by: Jiayuan Chen <jiayuan.chen(a)linux.dev>
Reported-by: syzbot+997752115a851cb0cf36(a)syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68e243a2.050a0220.1696c6.007d.GAE@google.com/T/
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Danilo Krummrich <dakr(a)kernel.org>
Cc: Dmitriy Vyukov <dvyukov(a)google.com>
Cc: Kees Cook <kees(a)kernel.org>
Cc: "Uladzislau Rezki (Sony)" <urezki(a)gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino(a)arm.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
include/linux/kasan.h | 21 +++++++++++++++++++--
mm/kasan/hw_tags.c | 4 ++--
mm/kasan/shadow.c | 6 ++++--
mm/vmalloc.c | 4 ++--
4 files changed, 27 insertions(+), 8 deletions(-)
--- a/include/linux/kasan.h~mm-kasan-fix-incorrect-unpoisoning-in-vrealloc-for-kasan
+++ a/include/linux/kasan.h
@@ -596,13 +596,23 @@ static inline void kasan_release_vmalloc
#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
- kasan_vmalloc_flags_t flags);
+ kasan_vmalloc_flags_t flags, bool reuse_tag);
+
+static __always_inline void *kasan_unpoison_vrealloc(const void *start,
+ unsigned long size,
+ kasan_vmalloc_flags_t flags)
+{
+ if (kasan_enabled())
+ return __kasan_unpoison_vmalloc(start, size, flags, true);
+ return (void *)start;
+}
+
static __always_inline void *kasan_unpoison_vmalloc(const void *start,
unsigned long size,
kasan_vmalloc_flags_t flags)
{
if (kasan_enabled())
- return __kasan_unpoison_vmalloc(start, size, flags);
+ return __kasan_unpoison_vmalloc(start, size, flags, false);
return (void *)start;
}
@@ -629,6 +639,13 @@ static inline void kasan_release_vmalloc
unsigned long free_region_end,
unsigned long flags) { }
+static inline void *kasan_unpoison_vrealloc(const void *start,
+ unsigned long size,
+ kasan_vmalloc_flags_t flags)
+{
+ return (void *)start;
+}
+
static inline void *kasan_unpoison_vmalloc(const void *start,
unsigned long size,
kasan_vmalloc_flags_t flags)
--- a/mm/kasan/hw_tags.c~mm-kasan-fix-incorrect-unpoisoning-in-vrealloc-for-kasan
+++ a/mm/kasan/hw_tags.c
@@ -317,7 +317,7 @@ static void init_vmalloc_pages(const voi
}
void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
- kasan_vmalloc_flags_t flags)
+ kasan_vmalloc_flags_t flags, bool reuse_tag)
{
u8 tag;
unsigned long redzone_start, redzone_size;
@@ -361,7 +361,7 @@ void *__kasan_unpoison_vmalloc(const voi
return (void *)start;
}
- tag = kasan_random_tag();
+ tag = reuse_tag ? get_tag(start) : kasan_random_tag();
start = set_tag(start, tag);
/* Unpoison and initialize memory up to size. */
--- a/mm/kasan/shadow.c~mm-kasan-fix-incorrect-unpoisoning-in-vrealloc-for-kasan
+++ a/mm/kasan/shadow.c
@@ -625,7 +625,7 @@ void kasan_release_vmalloc(unsigned long
}
void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
- kasan_vmalloc_flags_t flags)
+ kasan_vmalloc_flags_t flags, bool reuse_tag)
{
/*
* Software KASAN modes unpoison both VM_ALLOC and non-VM_ALLOC
@@ -648,7 +648,9 @@ void *__kasan_unpoison_vmalloc(const voi
!(flags & KASAN_VMALLOC_PROT_NORMAL))
return (void *)start;
- start = set_tag(start, kasan_random_tag());
+ if (!reuse_tag)
+ start = set_tag(start, kasan_random_tag());
+
kasan_unpoison(start, size, false);
return (void *)start;
}
--- a/mm/vmalloc.c~mm-kasan-fix-incorrect-unpoisoning-in-vrealloc-for-kasan
+++ a/mm/vmalloc.c
@@ -4175,8 +4175,8 @@ void *vrealloc_node_align_noprof(const v
* We already have the bytes available in the allocation; use them.
*/
if (size <= alloced_size) {
- kasan_unpoison_vmalloc(p + old_size, size - old_size,
- KASAN_VMALLOC_PROT_NORMAL);
+ kasan_unpoison_vrealloc(p, size,
+ KASAN_VMALLOC_PROT_NORMAL | KASAN_VMALLOC_VM_ALLOC);
/*
* No need to zero memory here, as unused memory will have
* already been zeroed at initial allocation time or during
_
Patches currently in -mm which might be from jiayuan.chen(a)linux.dev are
mm-kasan-fix-incorrect-unpoisoning-in-vrealloc-for-kasan.patch
mm-vmscan-skip-increasing-kswapd_failures-when-reclaim-was-boosted.patch
handshake_req_submit() replaces sk->sk_destruct but never restores it when
submission fails before the request is hashed. handshake_sk_destruct() then
returns early and the original destructor never runs, leaking the socket.
Restore sk_destruct on the error path.
Fixes: 3b3009ea8abb ("net/handshake: Create a NETLINK service for handling handshake requests")
Reviewed-by: Chuck Lever <chuck.lever(a)oracle.com>
Cc: stable(a)vger.kernel.org
Signed-off-by: caoping <caoping(a)cmss.chinamobile.com>
---
net/handshake/request.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/handshake/request.c b/net/handshake/request.c
index 274d2c89b6b2..89435ed755cd 100644
--- a/net/handshake/request.c
+++ b/net/handshake/request.c
@@ -276,6 +276,8 @@ int handshake_req_submit(struct socket *sock, struct handshake_req *req,
out_unlock:
spin_unlock(&hn->hn_lock);
out_err:
+ /* Restore original destructor so socket teardown still runs on failure */
+ req->hr_sk->sk_destruct = req->hr_odestruct;
trace_handshake_submit_err(net, req, req->hr_sk, ret);
handshake_req_destroy(req);
return ret;
base-commit: 4a26e7032d7d57c998598c08a034872d6f0d3945
--
2.47.3
When ECAM is enabled, the driver skipped calling dw_pcie_iatu_setup()
before configuring ECAM iATU entries. This left IO and MEM outbound
windows unprogrammed, resulting in broken IO transactions. Additionally,
dw_pcie_config_ecam_iatu() was only called during host initialization,
so ECAM-related iATU entries were not restored after suspend/resume,
leading to failures in configuration space access.
To resolve these issues, the ECAM iATU configuration is moved into
dw_pcie_setup_rc(). At the same time, dw_pcie_iatu_setup() is invoked
when ECAM is enabled.
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru(a)oss.qualcomm.com>
---
Krishna Chaitanya Chundru (2):
PCI: dwc: Correct iATU index increment for MSG TLP region
PCI: dwc: Fix missing iATU setup when ECAM is enabled
drivers/pci/controller/dwc/pcie-designware-host.c | 37 ++++++++++++++---------
drivers/pci/controller/dwc/pcie-designware.c | 3 ++
drivers/pci/controller/dwc/pcie-designware.h | 2 +-
3 files changed, 26 insertions(+), 16 deletions(-)
---
base-commit: 3f9f0252130e7dd60d41be0802bf58f6471c691d
change-id: 20251203-ecam_io_fix-6e060fecd3b8
Best regards,
--
Krishna Chaitanya Chundru <krishna.chundru(a)oss.qualcomm.com>
intel_dmc_update_dc6_allowed_count() oopses when DMC hasn't been
initialized, and dmc is thus NULL.
That would be the case when the call path is
intel_power_domains_init_hw() -> {skl,bxt,icl}_display_core_init() ->
gen9_set_dc_state() -> intel_dmc_update_dc6_allowed_count(), as
intel_power_domains_init_hw() is called *before* intel_dmc_init().
However, gen9_set_dc_state() calls intel_dmc_update_dc6_allowed_count()
conditionally, depending on the current and target DC states. At probe,
the target is disabled, but if DC6 is enabled, the function is called,
and an oops follows. Apparently it's quite unlikely that DC6 is enabled
at probe, as we haven't seen this failure mode before.
Add NULL checks and switch the dmc->display references to just display.
Fixes: 88c1f9a4d36d ("drm/i915/dmc: Create debugfs entry for dc6 counter")
Cc: Mohammed Thasleem <mohammed.thasleem(a)intel.com>
Cc: Imre Deak <imre.deak(a)intel.com>
Cc: <stable(a)vger.kernel.org> # v6.16+
Signed-off-by: Jani Nikula <jani.nikula(a)intel.com>
---
Rare case, but this may also throw off the rc6 counting in debugfs when
it does happen.
---
drivers/gpu/drm/i915/display/intel_dmc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
index 2fb6fec6dc99..169bbbc91f6d 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -1570,10 +1570,10 @@ void intel_dmc_update_dc6_allowed_count(struct intel_display *display,
struct intel_dmc *dmc = display_to_dmc(display);
u32 dc5_cur_count;
- if (DISPLAY_VER(dmc->display) < 14)
+ if (!dmc || DISPLAY_VER(display) < 14)
return;
- dc5_cur_count = intel_de_read(dmc->display, DG1_DMC_DEBUG_DC5_COUNT);
+ dc5_cur_count = intel_de_read(display, DG1_DMC_DEBUG_DC5_COUNT);
if (!start_tracking)
dmc->dc6_allowed.count += dc5_cur_count - dmc->dc6_allowed.dc5_start;
@@ -1587,7 +1587,7 @@ static bool intel_dmc_get_dc6_allowed_count(struct intel_display *display, u32 *
struct intel_dmc *dmc = display_to_dmc(display);
bool dc6_enabled;
- if (DISPLAY_VER(display) < 14)
+ if (!dmc || DISPLAY_VER(display) < 14)
return false;
mutex_lock(&power_domains->lock);
--
2.47.3
From: Alan Stern <stern(a)rowland.harvard.edu>
[ Upstream commit a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd ]
Testing by the syzbot fuzzer showed that the HID core gets a
shift-out-of-bounds exception when it tries to convert a 32-bit
quantity to a 0-bit quantity. Ideally this should never occur, but
there are buggy devices and some might have a report field with size
set to zero; we shouldn't reject the report or the device just because
of that.
Instead, harden the s32ton() routine so that it returns a reasonable
result instead of crashing when it is called with the number of bits
set to 0 -- the same as what snto32() does.
Signed-off-by: Alan Stern <stern(a)rowland.harvard.edu>
Reported-by: syzbot+b63d677d63bcac06cf90(a)syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-usb/68753a08.050a0220.33d347.0008.GAE@google.…
Tested-by: syzbot+b63d677d63bcac06cf90(a)syzkaller.appspotmail.com
Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split")
Cc: stable(a)vger.kernel.org
Link: https://patch.msgid.link/613a66cd-4309-4bce-a4f7-2905f9bce0c9@rowland.harva…
Signed-off-by: Benjamin Tissoires <bentiss(a)kernel.org>
[ s32ton() was moved by c653ffc28340 ("HID: stop exporting hid_snto32()").
Minor context change fixed. ]
Signed-off-by: Wenshan Lan <jetlan9(a)163.com>
---
drivers/hid/hid-core.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 89aa7a0e51de..e789452181fe 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1349,7 +1349,12 @@ EXPORT_SYMBOL_GPL(hid_snto32);
static u32 s32ton(__s32 value, unsigned n)
{
- s32 a = value >> (n - 1);
+ s32 a;
+
+ if (!value || !n)
+ return 0;
+
+ a = value >> (n - 1);
if (a && a != -1)
return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
return value & ((1 << n) - 1);
--
2.43.0
From: Alan Stern <stern(a)rowland.harvard.edu>
[ Upstream commit a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd ]
Testing by the syzbot fuzzer showed that the HID core gets a
shift-out-of-bounds exception when it tries to convert a 32-bit
quantity to a 0-bit quantity. Ideally this should never occur, but
there are buggy devices and some might have a report field with size
set to zero; we shouldn't reject the report or the device just because
of that.
Instead, harden the s32ton() routine so that it returns a reasonable
result instead of crashing when it is called with the number of bits
set to 0 -- the same as what snto32() does.
Signed-off-by: Alan Stern <stern(a)rowland.harvard.edu>
Reported-by: syzbot+b63d677d63bcac06cf90(a)syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-usb/68753a08.050a0220.33d347.0008.GAE@google.…
Tested-by: syzbot+b63d677d63bcac06cf90(a)syzkaller.appspotmail.com
Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split")
Cc: stable(a)vger.kernel.org
Link: https://patch.msgid.link/613a66cd-4309-4bce-a4f7-2905f9bce0c9@rowland.harva…
Signed-off-by: Benjamin Tissoires <bentiss(a)kernel.org>
[ s32ton() was moved by c653ffc28340 ("HID: stop exporting hid_snto32()").
Minor context change fixed. ]
Signed-off-by: Wenshan Lan <jetlan9(a)163.com>
---
drivers/hid/hid-core.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index a6c2c55daebb..d49a8c458206 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1349,7 +1349,12 @@ EXPORT_SYMBOL_GPL(hid_snto32);
static u32 s32ton(__s32 value, unsigned n)
{
- s32 a = value >> (n - 1);
+ s32 a;
+
+ if (!value || !n)
+ return 0;
+
+ a = value >> (n - 1);
if (a && a != -1)
return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
return value & ((1 << n) - 1);
--
2.43.0