linux-stable.git/include, branch v6.18.49 Linux kernel stable tree kunit: irq: Continue increasing hrtimer interval for longer 2026-09-02T12:31:50+00:00 Eric Biggers ebiggers@kernel.org 2026-08-03T18:18:41+00:00 e90bc78125cd7a36d0ef166f681c62a584156fe5 commit faa6c4c4e4ac69926564688a926105621295d613 upstream. Currently, kunit_irq_test_timer_func() stops increasing the hrtimer interval as soon as some forward progress is made in each of softirq and task context. Update it to use a more aggressive strategy: increase the interval as long as the hrtimer is running significantly faster than either context. This resolves an occasional hang in the CRC and crypto library tests under qemu-system-s390x. It was exposed by the change in the default preemption model on s390 from NONE to LAZY. That seems to have exposed the issue by allowing some forward progress to be made while the actual system timer tick is still starved, preventing jiffies from increasing or the task context from making much progress towards max_iterations. Fixes: 201ceb94aa1d ("kunit: irq: Ensure timer doesn't fire too frequently") Cc: stable@vger.kernel.org Reviewed-by: David Gow <david@davidgow.net> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://patch.msgid.link/20260803181842.44648-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit faa6c4c4e4ac69926564688a926105621295d613 upstream.

Currently, kunit_irq_test_timer_func() stops increasing the hrtimer
interval as soon as some forward progress is made in each of softirq and
task context.  Update it to use a more aggressive strategy: increase the
interval as long as the hrtimer is running significantly faster than
either context.

This resolves an occasional hang in the CRC and crypto library tests
under qemu-system-s390x.  It was exposed by the change in the default
preemption model on s390 from NONE to LAZY.  That seems to have exposed
the issue by allowing some forward progress to be made while the actual
system timer tick is still starved, preventing jiffies from increasing
or the task context from making much progress towards max_iterations.

Fixes: 201ceb94aa1d ("kunit: irq: Ensure timer doesn't fire too frequently")
Cc: stable@vger.kernel.org
Reviewed-by: David Gow <david@davidgow.net>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://patch.msgid.link/20260803181842.44648-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
batman-adv: reject unrepresentable multicast TVLV offsets 2026-09-02T12:31:50+00:00 Kyle Zeng kylebot@openai.com 2026-08-17T08:49:54+00:00 916ec741e65af072b98e475feaad98c063da1b7c commit f12c2de4f542e3220e17e0606f492110064f04cb upstream. The network and transport header fields in struct sk_buff are 16-bit offsets from skb->head, and U16_MAX is reserved as the unset transport header value. batadv_tvlv_call_handler() sets both fields from a received multicast TVLV without checking whether the TVLV end is representable. If the end offset exceeds the field's range, skb_set_transport_header() truncates it so that the transport header precedes the network header. The negative difference is then returned by skb_network_header_len() as a large u32. batadv_mcast_forw_packet() consequently accepts an oversized multicast tracker and accesses memory beyond the skb data. Add skb_set_transport_header_careful(), an offset-aware counterpart to skb_reset_transport_header_careful(), which validates the final head-relative offset before assigning it. Use the new helper in batadv_tvlv_call_handler() and reject unrepresentable TVLVs before setting the network header. Fixes: 07afe1ba288c ("batman-adv: mcast: implement multicast packet reception and forwarding") Cc: stable@vger.kernel.org Signed-off-by: Kyle Zeng <kylebot@openai.com> Co-developed-by: David Lee <david.lee@trailofbits.com> Signed-off-by: David Lee <david.lee@trailofbits.com> Acked-by: Sven Eckelmann <sven@narfation.org> Link: https://patch.msgid.link/20260817084955.944189-1-david.lee@trailofbits.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f12c2de4f542e3220e17e0606f492110064f04cb upstream.

The network and transport header fields in struct sk_buff are 16-bit
offsets from skb->head, and U16_MAX is reserved as the unset transport
header value. batadv_tvlv_call_handler() sets both fields from a received
multicast TVLV without checking whether the TVLV end is representable.

If the end offset exceeds the field's range, skb_set_transport_header()
truncates it so that the transport header precedes the network header.
The negative difference is then returned by skb_network_header_len() as
a large u32. batadv_mcast_forw_packet() consequently accepts an oversized
multicast tracker and accesses memory beyond the skb data.

Add skb_set_transport_header_careful(), an offset-aware counterpart to
skb_reset_transport_header_careful(), which validates the final
head-relative offset before assigning it. Use the new helper in
batadv_tvlv_call_handler() and reject unrepresentable TVLVs before
setting the network header.

Fixes: 07afe1ba288c ("batman-adv: mcast: implement multicast packet reception and forwarding")
Cc: stable@vger.kernel.org
Signed-off-by: Kyle Zeng <kylebot@openai.com>
Co-developed-by: David Lee <david.lee@trailofbits.com>
Signed-off-by: David Lee <david.lee@trailofbits.com>
Acked-by: Sven Eckelmann <sven@narfation.org>
Link: https://patch.msgid.link/20260817084955.944189-1-david.lee@trailofbits.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: f_tcm: keep port count until LUN teardown completes 2026-09-02T12:31:48+00:00 Shuangpeng Bai shuangpeng.kernel@gmail.com 2026-08-07T06:07:33+00:00 85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95 commit c39d0916da47d94909391876c9e5bd429ea7b1b9 upstream. tcm_usbg_drop_nexus() permits session removal once tpg_port_count reaches zero. However, usbg_port_unlink() currently decrements that count from the fabric_pre_unlink() callback, before core_dev_del_lun() waits for active se_lun references to drain. If removal of the last LUN races a nexus removal, the latter can observe a zero port count and call target_remove_session(). This frees sess_cmd_map while an in-flight struct usbg_cmd, including its work item, can still be accessed. Overlapping the last-LUN unlink with nexus removal reproduces this lifetime violation as a DEBUG_OBJECTS "free active" warning for usbg_cmd_work, followed by a target-core BUG/Oops. The generic target-core unlink path has no callback after core_dev_del_lun() completes. Add an optional fabric_post_unlink() callback and use it for the f_tcm port count. The count now remains nonzero until core_dev_del_lun() has finished draining active LUN references, preventing nexus removal from freeing the session during command completion. Fixes: c52661d60f63 ("usb-gadget: Initial merge of target module for UASP + BOT") Cc: stable@vger.kernel.org Signed-off-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com> Link: https://patch.msgid.link/20260807060733.3186624-1-shuangpeng.kernel@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c39d0916da47d94909391876c9e5bd429ea7b1b9 upstream.

tcm_usbg_drop_nexus() permits session removal once tpg_port_count
reaches zero. However, usbg_port_unlink() currently decrements that
count from the fabric_pre_unlink() callback, before core_dev_del_lun()
waits for active se_lun references to drain.

If removal of the last LUN races a nexus removal, the latter can observe
a zero port count and call target_remove_session(). This frees
sess_cmd_map while an in-flight struct usbg_cmd, including its work item,
can still be accessed.

Overlapping the last-LUN unlink with nexus removal reproduces this
lifetime violation as a DEBUG_OBJECTS "free active" warning for
usbg_cmd_work, followed by a target-core BUG/Oops.

The generic target-core unlink path has no callback after
core_dev_del_lun() completes. Add an optional fabric_post_unlink()
callback and use it for the f_tcm port count. The count now remains
nonzero until core_dev_del_lun() has finished draining active LUN
references, preventing nexus removal from freeing the session during
command completion.

Fixes: c52661d60f63 ("usb-gadget: Initial merge of target module for UASP + BOT")
Cc: stable@vger.kernel.org
Signed-off-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Link: https://patch.msgid.link/20260807060733.3186624-1-shuangpeng.kernel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring: defer eventfd signaling when queued from a wakeup handler 2026-09-02T12:31:47+00:00 Jens Axboe axboe@kernel.dk 2026-08-25T19:47:44+00:00 e22f4494cc9487d326e5e3067f33dea7c1e442b2 [ Upstream commit cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e ] io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline. Fixes: 21a091b970cd ("io_uring: signal registered eventfd to process deferred task work") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20260813133843.2933127-1-4ncienth@gmail.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk> [ Relocated the `io_req_local_work_add()` hunk into io_uring.c and kept 6.18's `ctx->has_evfd` and open-coded `io_pollfree_wake()` context due to missing tw.c split and `io_poll_remove_waitq()`. ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e ]

io_req_local_work_add() signals the CQ ring eventfd inline when it is the
one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that
add is frequently done from a waitqueue wakeup handler, where an
arbitrary waitqueue lock is held.

eventfd_signal_mask() only refuses to recurse when current->in_eventfd
is set, but that bit is set by eventfd_signal_mask() itself. If the wake
chain starts somewhere else, signal goes out inline and can feed back
into epoll.

Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three
waitqueue callbacks, and use it to force io_eventfd_signal() down the
existing call_rcu_hurry() deferral instead of signaling inline.

Fixes: 21a091b970cd ("io_uring: signal registered eventfd to process deferred task work")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20260813133843.2933127-1-4ncienth@gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[ Relocated the `io_req_local_work_add()` hunk into io_uring.c and kept 6.18's `ctx->has_evfd` and open-coded `io_pollfree_wake()` context due to missing tw.c split and `io_poll_remove_waitq()`. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
futex: Fix might_sleep() warning in futex_pivot_pending() 2026-08-27T12:32:54+00:00 Peter Zijlstra peterz@infradead.org 2026-08-25T12:48:14+00:00 942b89f7824f833318fa7c4d1ed9abeb679947b7 commit d8aa5dd97944a72d4a9e3cc79bb80fcac7d6e829 upstream. A younger me put a WARN in might_sleep() to warn about nested sleep loops. This younger me also build a wait-loop variant that can deal with it. This wait-loop variant doesn't have all the fancy wrappers, since it isn't used much. It also lacks wait-bit support. Add the wait-bit support and use it to fix the nested wait issue. Fixes: 8e7ff730dd96 ("futex: Fix race in futex_pivot_pending() during private hash resize") Reported-by: syzbot+350a93852ac854927f45@syzkaller.appspotmail.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260820074927.GH1246887@noisy.programming.kicks-ass.net Closes: https://syzkaller.appspot.com/bug?extid=350a93852ac854927f45 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d8aa5dd97944a72d4a9e3cc79bb80fcac7d6e829 upstream.

A younger me put a WARN in might_sleep() to warn about nested sleep loops. This
younger me also build a wait-loop variant that can deal with it. This wait-loop
variant doesn't have all the fancy wrappers, since it isn't used much. It also
lacks wait-bit support.

Add the wait-bit support and use it to fix the nested wait issue.

Fixes: 8e7ff730dd96 ("futex: Fix race in futex_pivot_pending() during private hash resize")
Reported-by: syzbot+350a93852ac854927f45@syzkaller.appspotmail.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260820074927.GH1246887@noisy.programming.kicks-ass.net
Closes: https://syzkaller.appspot.com/bug?extid=350a93852ac854927f45
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
futex/pi: Plug private futex exec() race 2026-08-27T12:32:53+00:00 Thomas Gleixner tglx@kernel.org 2026-08-25T12:48:05+00:00 fdf538b2e69653ff740e84042245018e5680cd7b commit c5f0bc9fd1cec4a00400cc727fcde03e0fde17cc upstream. The check for private futexes whether the waiter's mm, which is stored in the futex_key and copied into the pi_state, is the same as the owner's mm is not sufficient for exec(). exec() has a gap where the mm check fails to give the correct answer: exec() ... exec_release_mm() futex_exec_release() tsk::futex::exit_state = EXITING; cleanup_robust_list(); 1) tsk::futex::exit_state = OK; ... old_mm = tsk::mm; 2) tsk::mm = ->mm; Between #1 and #2 the check for the mm is wrong as that mm is about to be swapped out and eventually freed. Plug this gap by: 1) Setting tsk::futex::exit_state to FUTEX_STATE_DEAD in futex_exec_release() 2) Setting tsk::futex::exit_state to FUTEX_STATE_OK after the mm has been switched. >>From a futex point of view the task is dead after it finished the robust list cleanup up to the point where it sets the state to OK again. Fixes: 80367ad01d93 ("futex: Add basic infrastructure for local task local hash") Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Kyle Zeng <kylebot@openai.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c5f0bc9fd1cec4a00400cc727fcde03e0fde17cc upstream.

The check for private futexes whether the waiter's mm, which is stored in
the futex_key and copied into the pi_state, is the same as the owner's mm
is not sufficient for exec(). exec() has a gap where the mm check fails to
give the correct answer:

  exec()
  ...
    exec_release_mm()
      futex_exec_release()
        tsk::futex::exit_state = EXITING;
        cleanup_robust_list();
1)      tsk::futex::exit_state = OK;
    ...
    old_mm = tsk::mm;
2)  tsk::mm = ->mm;

Between #1 and #2 the check for the mm is wrong as that mm is about to be
swapped out and eventually freed.

Plug this gap by:

  1) Setting tsk::futex::exit_state to FUTEX_STATE_DEAD in
     futex_exec_release()

  2) Setting tsk::futex::exit_state to FUTEX_STATE_OK after
     the mm has been switched.

>>From a futex point of view the task is dead after it finished the robust
list cleanup up to the point where it sets the state to OK again.

Fixes: 80367ad01d93 ("futex: Add basic infrastructure for local task local hash")
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Kyle Zeng <kylebot@openai.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kcov: fix data corruption and race conditions on PREEMPT_RT 2026-08-27T12:32:50+00:00 Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp 2026-07-15T23:01:29+00:00 e11f5b48c82703242a3be7a7ae4b4940b4cb4610 commit 2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c upstream. syzbot is reporting KCOV state corruption on PREEMPT_RT kernels, for the temporary storage used for saving/restoring remote KCOV state is currently allocated as the per-CPU area. On PREEMPT_RT kernels, softirq handlers run as preemptible task threads (e.g., ksoftirqd). If a softirq context preempts a task running a remote KCOV session, it safely saves the task's state into the per-CPU area. However, if that softirq thread is subsequently preempted by a higher- priority softirq thread on the same CPU, the second softirq will overwrite the same per-CPU area, permanently destroying the original task's KCOV state. Fix this data corruption by moving the temporary storage from the per-CPU area to the per-thread area. Since each softirq thread now owns its own task context, nested softirq preemption no longer causes data overwrites. Note that while the temporary storage is now on a per-thread basis, the per-CPU kcov_percpu_data.lock must be retained, for we need to ensure that kcov_remote_start() and kcov_remote_stop() operate atomically without racing against asynchronous interrupts that manipulate the current task's KCOV state. It is likely that GFP_KERNEL allocation by vmalloc_node() in kcov_init() has already called panic() before returning NULL, for there will be no OOM-killable userspace processes when __init function of built-in module runs. But this patch also fixes crashing the kernel when vmalloc_node() in kcov_init() returned NULL, for kcov_init() left per-CPU irq_area == NULL but kcov_remote_start() depends on per-CPU irq_area != NULL, resulting in (1) doing vmalloc() in kcov_remote_start() despite !in_task() context (2) out-of-array-bounds access if (1) succeeded but kcov->remote_size < CONFIG_KCOV_IRQ_AREA_SIZE (3) always leak memory allocated by (1), eventually killing all OOM-killable userspace processes problems. Link: https://lore.kernel.org/43552d09-2ce2-4b19-b0d3-a2d1ab952145@I-love.SAKURA.ne.jp Reported-by: syzbot+3f51ad7ac3ae57a6fdcc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3f51ad7ac3ae57a6fdcc Reported-by: syzbot+47cf95ca1f9dcca872c8@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=47cf95ca1f9dcca872c8 Reported-by: syzbot+8a173e13208949931dc7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=8a173e13208949931dc7 Reported-by: syzbot+90984d3713722683112e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=90984d3713722683112e Analyzed-by: AI Mode in Google Search (no mail address) Fixes: 5ff3b30ab57d ("kcov: collect coverage from interrupts") Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Clark Williams <williams@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Marco Elver <elver@google.com> Cc: Mark Brown <broonie@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c upstream.

syzbot is reporting KCOV state corruption on PREEMPT_RT kernels, for the
temporary storage used for saving/restoring remote KCOV state is currently
allocated as the per-CPU area.

On PREEMPT_RT kernels, softirq handlers run as preemptible task threads
(e.g., ksoftirqd). If a softirq context preempts a task running a remote
KCOV session, it safely saves the task's state into the per-CPU area.
However, if that softirq thread is subsequently preempted by a higher-
priority softirq thread on the same CPU, the second softirq will overwrite
the same per-CPU area, permanently destroying the original task's KCOV
state.

Fix this data corruption by moving the temporary storage from the per-CPU
area to the per-thread area. Since each softirq thread now owns its own
task context, nested softirq preemption no longer causes data overwrites.

Note that while the temporary storage is now on a per-thread basis, the
per-CPU kcov_percpu_data.lock must be retained, for we need to ensure that
kcov_remote_start() and kcov_remote_stop() operate atomically without
racing against asynchronous interrupts that manipulate the current task's
KCOV state.

It is likely that GFP_KERNEL allocation by vmalloc_node() in kcov_init()
has already called panic() before returning NULL, for there will be no
OOM-killable userspace processes when __init function of built-in module
runs. But this patch also fixes crashing the kernel when vmalloc_node()
in kcov_init() returned NULL, for kcov_init() left per-CPU irq_area == NULL
but kcov_remote_start() depends on per-CPU irq_area != NULL, resulting in

  (1) doing vmalloc() in kcov_remote_start() despite !in_task() context

  (2) out-of-array-bounds access if (1) succeeded but
      kcov->remote_size < CONFIG_KCOV_IRQ_AREA_SIZE

  (3) always leak memory allocated by (1), eventually killing all
      OOM-killable userspace processes

problems.

Link: https://lore.kernel.org/43552d09-2ce2-4b19-b0d3-a2d1ab952145@I-love.SAKURA.ne.jp
Reported-by: syzbot+3f51ad7ac3ae57a6fdcc@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=3f51ad7ac3ae57a6fdcc
Reported-by: syzbot+47cf95ca1f9dcca872c8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=47cf95ca1f9dcca872c8
Reported-by: syzbot+8a173e13208949931dc7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=8a173e13208949931dc7
Reported-by: syzbot+90984d3713722683112e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=90984d3713722683112e
Analyzed-by: AI Mode in Google Search (no mail address)
Fixes: 5ff3b30ab57d ("kcov: collect coverage from interrupts")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PCI: host-generic: Fix NULL pointer dereference on 32-bit CAM systems 2026-08-27T12:32:49+00:00 Steffen Persvold spersvold@gmail.com 2026-07-09T12:24:46+00:00 0c55707bd5d0d7670704cfd0dda933809b052f67 commit 008cb88edb41f3c7c8e0ed763ff9f26719830984 upstream. On 32-bit systems the config space is too large to ioremap in one go, so pci_ecam_create() maps each bus segment separately and relies on the ->add_bus callback (pci_ecam_add_bus) to populate the per-bus mapping in cfg->winp[]. pci_ecam_map_bus() then uses that mapping as the base for every config access. The generic ECAM ops (pci_generic_ecam_ops) already provide the ->add_bus and ->remove_bus callbacks, but the CAM (legacy) ops in pci-host-generic.c do not. As a result, on a 32-bit host using "pci-host-cam-generic" the per-bus mapping is never set up and the first config read dereferences a NULL base, crashing during bus enumeration: Unable to handle kernel NULL pointer dereference at virtual address 00000800 Oops [#1] CPU: 0 PID: 1 Comm: swapper Not tainted 6.9.7+ #43 Hardware name: Digilent Nexys-Video-A7 RV32 (DT) epc : pci_generic_config_read+0x40/0xb0 ra : pci_generic_config_read+0x2c/0xb0 [<c038db9c>] pci_generic_config_read+0x40/0xb0 [<c038da04>] pci_bus_read_config_dword+0x50/0xb0 [<c0391e94>] pci_bus_generic_read_dev_vendor_id+0x3c/0x1ec [<c039245c>] pci_scan_single_device+0xa4/0x11c [<c0392570>] pci_scan_slot+0x9c/0x23c [<c039388c>] pci_scan_child_bus_extend+0x58/0x2f4 [<c0393db0>] pci_scan_root_bus_bridge+0x64/0xe8 [<c0393e54>] pci_host_probe+0x20/0xc8 [<c03bc6f4>] pci_host_common_probe+0x144/0x1e4 Fix this by giving the CAM ops the same ->add_bus/->remove_bus callbacks. Since pci_ecam_add_bus() and pci_ecam_remove_bus() are static to ecam.c, move the CAM ops definition there as pci_generic_cam_ops (mirroring pci_generic_ecam_ops) and export it for pci-host-generic.c to reference. Fixes: 8fe55ef23387 ("PCI: Dynamically map ECAM regions") Signed-off-by: Steffen Persvold <spersvold@gmail.com> [mani: removed timestamp from log] Signed-off-by: Manivannan Sadhasivam <mani@kernel.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260709122446.3151899-1-spersvold@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 008cb88edb41f3c7c8e0ed763ff9f26719830984 upstream.

On 32-bit systems the config space is too large to ioremap in one go, so
pci_ecam_create() maps each bus segment separately and relies on the
->add_bus callback (pci_ecam_add_bus) to populate the per-bus mapping in
cfg->winp[]. pci_ecam_map_bus() then uses that mapping as the base for
every config access.

The generic ECAM ops (pci_generic_ecam_ops) already provide the ->add_bus
and ->remove_bus callbacks, but the CAM (legacy) ops in pci-host-generic.c
do not. As a result, on a 32-bit host using "pci-host-cam-generic" the
per-bus mapping is never set up and the first config read dereferences a
NULL base, crashing during bus enumeration:

 Unable to handle kernel NULL pointer dereference at virtual address 00000800
 Oops [#1]
 CPU: 0 PID: 1 Comm: swapper Not tainted 6.9.7+ #43
 Hardware name: Digilent Nexys-Video-A7 RV32 (DT)
 epc : pci_generic_config_read+0x40/0xb0
  ra : pci_generic_config_read+0x2c/0xb0
 [<c038db9c>] pci_generic_config_read+0x40/0xb0
 [<c038da04>] pci_bus_read_config_dword+0x50/0xb0
 [<c0391e94>] pci_bus_generic_read_dev_vendor_id+0x3c/0x1ec
 [<c039245c>] pci_scan_single_device+0xa4/0x11c
 [<c0392570>] pci_scan_slot+0x9c/0x23c
 [<c039388c>] pci_scan_child_bus_extend+0x58/0x2f4
 [<c0393db0>] pci_scan_root_bus_bridge+0x64/0xe8
 [<c0393e54>] pci_host_probe+0x20/0xc8
 [<c03bc6f4>] pci_host_common_probe+0x144/0x1e4

Fix this by giving the CAM ops the same ->add_bus/->remove_bus callbacks.
Since pci_ecam_add_bus() and pci_ecam_remove_bus() are static to ecam.c,
move the CAM ops definition there as pci_generic_cam_ops (mirroring
pci_generic_ecam_ops) and export it for pci-host-generic.c to reference.

Fixes: 8fe55ef23387 ("PCI: Dynamically map ECAM regions")
Signed-off-by: Steffen Persvold <spersvold@gmail.com>
[mani: removed timestamp from log]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260709122446.3151899-1-spersvold@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drm/client: Remove drm_client_framebuffer_delete() 2026-08-23T12:27:09+00:00 Thomas Zimmermann tzimmermann@suse.de 2025-10-27T12:09:16+00:00 a6325e2807dc2b985a2fea363794e0ed52e02698 [ Upstream commit 3e3153325fd3693d0f9fe235c4afbcd68ef102e1 ] Release client buffers with drm_client_buffer_delete() instead of drm_client_framebuffer_delete(). The latter is just a tiny wrapper around the former. Move the test for !buffer into drm_client_buffer_delete(), although all callers appear to always have a valid pointer. v2: - test for !buffer before deref-ing pointer (Jocelyn, Dan) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Tested-by: Francesco Valla <francesco@valla.it> Link: https://patch.msgid.link/20251027121042.143588-6-tzimmermann@suse.de Stable-dep-of: f4f2bba28df9 ("drm/log: Fix infinite loop when scale is too large for display") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3e3153325fd3693d0f9fe235c4afbcd68ef102e1 ]

Release client buffers with drm_client_buffer_delete() instead of
drm_client_framebuffer_delete(). The latter is just a tiny wrapper
around the former.

Move the test for !buffer into drm_client_buffer_delete(), although
all callers appear to always have a valid pointer.

v2:
- test for !buffer before deref-ing pointer (Jocelyn, Dan)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Tested-by: Francesco Valla <francesco@valla.it>
Link: https://patch.msgid.link/20251027121042.143588-6-tzimmermann@suse.de
Stable-dep-of: f4f2bba28df9 ("drm/log: Fix infinite loop when scale is too large for display")
Signed-off-by: Sasha Levin <sashal@kernel.org>
drm/client: Deprecate struct drm_client_buffer.gem 2026-08-23T12:27:09+00:00 Thomas Zimmermann tzimmermann@suse.de 2025-10-27T12:09:15+00:00 329731b3119f0cd3fe68f650f844462dad4895e8 [ Upstream commit ea39f2e66e61035e203530977a3df428345d03e2 ] The client buffer's framebuffer holds a reference and pointer on each of its GEM buffer objects. Thus the field gem in the client- buffer struct is not necessary. Deprecated the field and convert the client-buffer helpers to use the framebuffer's objects. In drm_client_buffer_delete(), do a possible vunmap before releasing the framebuffer. Otherwise we'd eventually release the framebuffer before unmaping its buffer objects. v2: - avoid dependency on CONFIG_DRM_KMS_HELPER Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Tested-by: Francesco Valla <francesco@valla.it> Link: https://patch.msgid.link/20251027121042.143588-5-tzimmermann@suse.de Stable-dep-of: f4f2bba28df9 ("drm/log: Fix infinite loop when scale is too large for display") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ea39f2e66e61035e203530977a3df428345d03e2 ]

The client buffer's framebuffer holds a reference and pointer on
each of its GEM buffer objects. Thus the field gem in the client-
buffer struct is not necessary. Deprecated the field and convert
the client-buffer helpers to use the framebuffer's objects.

In drm_client_buffer_delete(), do a possible vunmap before releasing
the framebuffer. Otherwise we'd eventually release the framebuffer
before unmaping its buffer objects.

v2:
- avoid dependency on CONFIG_DRM_KMS_HELPER

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Tested-by: Francesco Valla <francesco@valla.it>
Link: https://patch.msgid.link/20251027121042.143588-5-tzimmermann@suse.de
Stable-dep-of: f4f2bba28df9 ("drm/log: Fix infinite loop when scale is too large for display")
Signed-off-by: Sasha Levin <sashal@kernel.org>