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| author | Dmitry Vyukov <dvyukov@google.com> | 2026-05-29 15:09:06 +0000 |
|---|---|---|
| committer | Danilo Krummrich <dakr@kernel.org> | 2026-06-08 20:21:27 +0200 |
| commit | d3ec78f8f8d48a04a9fac38d47275c34645e5103 (patch) | |
| tree | b991f8e6f90815f4cccafe7302e43b4bf3b9092b /drivers/base | |
| parent | fda8355f13ea3c0f9499acdeff3024995b474948 (diff) | |
| download | linux-next-d3ec78f8f8d48a04a9fac38d47275c34645e5103.tar.gz linux-next-d3ec78f8f8d48a04a9fac38d47275c34645e5103.zip | |
firmware_loader: Fix recursive lock in device_cache_fw_images()
A recursive locking deadlock can occur in the firmware loader's power
management notification handler.
During system suspend or hibernation preparation, fw_pm_notify() calls
device_cache_fw_images(). This function acquires fw_lock to set the
firmware cache state to FW_LOADER_START_CACHE and then iterates over all
devices using dpm_for_each_dev() while still holding the lock.
For each device, dev_cache_fw_image() schedules asynchronous work to cache
the firmware. If memory allocation for the async work entry fails (e.g., in
out-of-memory conditions), async_schedule_node_domain() falls back to
executing the work function synchronously in the current thread.
The synchronous execution path (__async_dev_cache_fw_image() ->
cache_firmware() -> request_firmware() -> assign_fw()) attempts to acquire
fw_lock again. Since the current thread already holds fw_lock, this results
in a recursive locking deadlock.
Fix this by releasing fw_lock immediately after updating the cache state
and before calling dpm_for_each_dev(). The lock is only needed to protect
the state update. Concurrent firmware requests will correctly see the
FW_LOADER_START_CACHE state and use the piggyback mechanism, which is
independently protected by its own fwc->name_lock.
Fixes: ac39b3ea73aa ("firmware loader: let caching firmware piggyback on loading firmware")
Assisted-by: Gemini:gemini-3.1-pro-preview Gemini:gemini-3-flash-preview syzbot
Reported-by: syzbot+e70e4c6f6eee43357ba7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e70e4c6f6eee43357ba7
Link: https://syzkaller.appspot.com/ai_job?id=8b4af9fd-24af-423f-8acb-1159fd34c1a5
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://patch.msgid.link/48b092a5-f49d-48a4-95f4-f65bebfc6bc3@mail.kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/firmware_loader/main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index a11b30dda23b..c96312ac2be7 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -1503,9 +1503,10 @@ static void device_cache_fw_images(void) mutex_lock(&fw_lock); fwc->state = FW_LOADER_START_CACHE; - dpm_for_each_dev(NULL, dev_cache_fw_image); mutex_unlock(&fw_lock); + dpm_for_each_dev(NULL, dev_cache_fw_image); + /* wait for completion of caching firmware for all devices */ async_synchronize_full_domain(&fw_cache_domain); |