* use-after-free in firmware_fallback_sysfs
@ 2025-09-04 4:58 Lalaev, Andrei
2025-09-11 22:35 ` Russ Weight
0 siblings, 1 reply; 5+ messages in thread
From: Lalaev, Andrei @ 2025-09-04 4:58 UTC (permalink / raw)
To: rafael@kernel.org, gregkh@linuxfoundation.org, dakr@kernel.org,
russ.weight@linux.dev, mcgrof@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
Andrei Lalaev
Hi,
We performed a long-term stability test on the LP5562 driver by repeatedly
downloading different LED firmwares using sysfs interface.
And after some time, we see the following "use-after-free" trace on kernel 6.12.11:
[ 274.759115] BUG: KASAN: slab-use-after-free in firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
[ 274.766743] Write of size 4 at addr b31d0850 by task kworker/2:2/137
[ 274.774680] CPU: 2 UID: 0 PID: 137 Comm: kworker/2:2 Tainted: G C 6.12.11 #1
[ 274.783208] Tainted: [C]=CRAP
[ 274.786215] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[ 274.792775] Workqueue: events request_firmware_work_func
[ 274.798151] Call trace:
[ 274.800720] dump_backtrace from show_stack (arch/arm/kernel/traps.c:259)
[ 274.805827] r7:600f0093 r6:600f0093 r5:b19659b4 r4:00000000
[ 274.811510] show_stack from dump_stack_lvl (lib/dump_stack.c:122)
[ 274.816613] dump_stack_lvl from print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
[ 274.822073] r7:000031d0 r6:df7dba00 r5:f13bbb20 r4:b31d0850
[ 274.827755] print_report from kasan_report (mm/kasan/report.c:603)
[ 274.832885] r10:b2d56c20 r9:cdc89808 r8:00003a98 r7:b0f653ac r6:00000004 r5:00000001
[ 274.840744] r4:b31d0850
[ 274.843298] kasan_report from __asan_report_store4_noabort (mm/kasan/report_generic.c:385)
[ 274.849804] r7:b9f72c00 r6:cdc89800 r5:b5d31e00 r4:b5d31e10
[ 274.855488] __asan_report_store4_noabort from firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
[ 274.863105] firmware_fallback_sysfs from _request_firmware (drivers/base/firmware_loader/main.c:941)
[ 274.869862] r10:f13bbda0 r9:b9f72c80 r8:b19c73d8 r7:00000004 r6:00000000 r5:b5d31e00
[ 274.877718] r4:f13bbd00
[ 274.880273] _request_firmware from request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
[ 274.887226] r10:b9f72e98 r9:b9f72e94 r8:f13bbde0 r7:173ee5d3 r6:00000000 r5:ad2777b0
[ 274.895097] r4:b9f72e80
[ 274.897661] request_firmware_work_func from process_one_work (kernel/workqueue.c:3235)
[ 274.904613] r10:00000000 r9:b7d7e1e0 r8:b7d7dd80 r7:d76b53c0 r6:b2013c00 r5:b9f72e80
[ 274.912469] r4:b2371a00
[ 274.915024] process_one_work from worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
[ 274.920823] r10:b2371a2c r9:b2371a00 r8:b9f72e84 r7:b2371a2c r6:d76b53dc r5:a546e345
[ 274.928678] r4:00000007
[ 274.931234] worker_thread from kthread (kernel/kthread.c:389)
[ 274.936179] r10:f0933ca0 r9:b2371a00 r8:b7f6b800 r7:b019ad18 r6:b2354880 r5:b7d7dd80
[ 274.944035] r4:b2354d00
[ 274.946592] kthread from ret_from_fork (arch/arm/kernel/entry-common.S:138)
[ 274.951350] Exception stack(0xf13bbfb0 to 0xf13bbff8)
[ 274.956435] bfa0: 00000000 00000000 00000000 00000000
[ 274.964647] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 274.972858] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[ 274.979508] r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:b01ba280
[ 274.987365] r4:b2354d00 r3:00000000
[ 274.992472] Allocated by task 8 on cpu 0 at 273.209883s:
[ 274.997814] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
[ 274.997858] kasan_save_alloc_info (mm/kasan/generic.c:566)
[ 274.997892] __kasan_kmalloc (mm/kasan/common.c:398)
[ 274.997926] __kmalloc_cache_noprof (mm/slub.c:4319)
[ 274.997957] alloc_lookup_fw_priv (drivers/base/firmware_loader/main.c:131 drivers/base/firmware_loader/main.c:190)
[ 274.997993] _request_firmware (drivers/base/firmware_loader/main.c:769 drivers/base/firmware_loader/main.c:899)
[ 274.998023] request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
[ 274.998055] process_one_work (kernel/workqueue.c:3235)
[ 274.998084] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
[ 274.998112] kthread (kernel/kthread.c:389)
[ 274.998149] ret_from_fork (arch/arm/kernel/entry-common.S:138)
[ 274.999686] Freed by task 8 on cpu 0 at 273.230581s:
[ 275.004679] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
[ 275.004718] kasan_save_free_info (mm/kasan/generic.c:582 (discriminator 1))
[ 275.004747] __kasan_slab_free (mm/kasan/common.c:271)
[ 275.004782] kfree (mm/slub.c:4601 (discriminator 3) mm/slub.c:4749 (discriminator 3))
[ 275.004810] free_fw_priv (drivers/base/firmware_loader/main.c:231)
[ 275.004840] release_firmware (drivers/base/firmware_loader/main.c:604 drivers/base/firmware_loader/main.c:1170 drivers/base/firmware_loader/main.c:1166)
[ 275.004871] lp55xx_firmware_loaded (drivers/leds/leds-lp55xx-common.c:549) leds_lp55xx_common
[ 275.005074] request_firmware_work_func (drivers/base/firmware_loader/main.c:1197)
[ 275.005112] process_one_work (kernel/workqueue.c:3235)
[ 275.005145] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
[ 275.005174] kthread (kernel/kthread.c:389)
[ 275.005212] ret_from_fork (arch/arm/kernel/entry-common.S:138)
[ 275.006754] The buggy address belongs to the object at b31d0800 which belongs to the cache kmalloc-128 of size 128
[ 275.018610] The buggy address is located 80 bytes inside of freed 128-byte region [b31d0800, b31d0880)
[ 275.030938] The buggy address belongs to the physical page:
[ 275.036533] page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x131d0
[ 275.036568] flags: 0x0(zone=0)
[ 275.036598] page_type: f5(slab)
[ 275.036634] raw: 00000000 b2001400 df9544e0 00000002 00000000 00100010 f5000000 00000001
[ 275.036659] page dumped because: kasan: bad access detected
[ 275.038189] Memory state around the buggy address:
[ 275.043008] b31d0700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 275.049563] b31d0780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 275.056120] >b31d0800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 275.062669] ^
[ 275.067831] b31d0880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 275.074386] b31d0900: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
[ 275.080938] ==================================================================
I couldn't find any related patches to fix this issue in upstream, so
I have made the following patch to address this issue, but I have some concerns about it.
Could someone please provide feedback or insights on this?
----
drivers/base/firmware_loader/main.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index c6664a787..1a49022f4 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -211,6 +211,7 @@ static void __free_fw_priv(struct kref *ref)
(unsigned int)fw_priv->size);
list_del(&fw_priv->list);
+ list_del(&fw_priv->pending_list);
spin_unlock(&fwc->lock);
if (fw_is_paged_buf(fw_priv))
----
Thanks a lot!
Best regards,
Andrei Lalaev
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: use-after-free in firmware_fallback_sysfs
2025-09-04 4:58 use-after-free in firmware_fallback_sysfs Lalaev, Andrei
@ 2025-09-11 22:35 ` Russ Weight
2025-09-12 10:13 ` Andrei Lalaev
0 siblings, 1 reply; 5+ messages in thread
From: Russ Weight @ 2025-09-11 22:35 UTC (permalink / raw)
To: Lalaev, Andrei
Cc: rafael@kernel.org, gregkh@linuxfoundation.org, dakr@kernel.org,
mcgrof@kernel.org, linux-kernel@vger.kernel.org,
linux-leds@vger.kernel.org, Andrei Lalaev
On Thu, Sep 04, 2025 at 04:58:45AM +0000, Lalaev, Andrei wrote:
> Hi,
>
> We performed a long-term stability test on the LP5562 driver by repeatedly
> downloading different LED firmwares using sysfs interface.
> And after some time, we see the following "use-after-free" trace on kernel 6.12.11:
>
> [ 274.759115] BUG: KASAN: slab-use-after-free in firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
> [ 274.766743] Write of size 4 at addr b31d0850 by task kworker/2:2/137
> [ 274.774680] CPU: 2 UID: 0 PID: 137 Comm: kworker/2:2 Tainted: G C 6.12.11 #1
> [ 274.783208] Tainted: [C]=CRAP
> [ 274.786215] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> [ 274.792775] Workqueue: events request_firmware_work_func
> [ 274.798151] Call trace:
> [ 274.800720] dump_backtrace from show_stack (arch/arm/kernel/traps.c:259)
> [ 274.805827] r7:600f0093 r6:600f0093 r5:b19659b4 r4:00000000
> [ 274.811510] show_stack from dump_stack_lvl (lib/dump_stack.c:122)
> [ 274.816613] dump_stack_lvl from print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
> [ 274.822073] r7:000031d0 r6:df7dba00 r5:f13bbb20 r4:b31d0850
> [ 274.827755] print_report from kasan_report (mm/kasan/report.c:603)
> [ 274.832885] r10:b2d56c20 r9:cdc89808 r8:00003a98 r7:b0f653ac r6:00000004 r5:00000001
> [ 274.840744] r4:b31d0850
> [ 274.843298] kasan_report from __asan_report_store4_noabort (mm/kasan/report_generic.c:385)
> [ 274.849804] r7:b9f72c00 r6:cdc89800 r5:b5d31e00 r4:b5d31e10
> [ 274.855488] __asan_report_store4_noabort from firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
> [ 274.863105] firmware_fallback_sysfs from _request_firmware (drivers/base/firmware_loader/main.c:941)
> [ 274.869862] r10:f13bbda0 r9:b9f72c80 r8:b19c73d8 r7:00000004 r6:00000000 r5:b5d31e00
> [ 274.877718] r4:f13bbd00
> [ 274.880273] _request_firmware from request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
> [ 274.887226] r10:b9f72e98 r9:b9f72e94 r8:f13bbde0 r7:173ee5d3 r6:00000000 r5:ad2777b0
> [ 274.895097] r4:b9f72e80
> [ 274.897661] request_firmware_work_func from process_one_work (kernel/workqueue.c:3235)
> [ 274.904613] r10:00000000 r9:b7d7e1e0 r8:b7d7dd80 r7:d76b53c0 r6:b2013c00 r5:b9f72e80
> [ 274.912469] r4:b2371a00
> [ 274.915024] process_one_work from worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
> [ 274.920823] r10:b2371a2c r9:b2371a00 r8:b9f72e84 r7:b2371a2c r6:d76b53dc r5:a546e345
> [ 274.928678] r4:00000007
> [ 274.931234] worker_thread from kthread (kernel/kthread.c:389)
> [ 274.936179] r10:f0933ca0 r9:b2371a00 r8:b7f6b800 r7:b019ad18 r6:b2354880 r5:b7d7dd80
> [ 274.944035] r4:b2354d00
> [ 274.946592] kthread from ret_from_fork (arch/arm/kernel/entry-common.S:138)
> [ 274.951350] Exception stack(0xf13bbfb0 to 0xf13bbff8)
> [ 274.956435] bfa0: 00000000 00000000 00000000 00000000
> [ 274.964647] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> [ 274.972858] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
> [ 274.979508] r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:b01ba280
> [ 274.987365] r4:b2354d00 r3:00000000
>
> [ 274.992472] Allocated by task 8 on cpu 0 at 273.209883s:
> [ 274.997814] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
> [ 274.997858] kasan_save_alloc_info (mm/kasan/generic.c:566)
> [ 274.997892] __kasan_kmalloc (mm/kasan/common.c:398)
> [ 274.997926] __kmalloc_cache_noprof (mm/slub.c:4319)
> [ 274.997957] alloc_lookup_fw_priv (drivers/base/firmware_loader/main.c:131 drivers/base/firmware_loader/main.c:190)
> [ 274.997993] _request_firmware (drivers/base/firmware_loader/main.c:769 drivers/base/firmware_loader/main.c:899)
> [ 274.998023] request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
> [ 274.998055] process_one_work (kernel/workqueue.c:3235)
> [ 274.998084] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
> [ 274.998112] kthread (kernel/kthread.c:389)
> [ 274.998149] ret_from_fork (arch/arm/kernel/entry-common.S:138)
>
> [ 274.999686] Freed by task 8 on cpu 0 at 273.230581s:
> [ 275.004679] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
> [ 275.004718] kasan_save_free_info (mm/kasan/generic.c:582 (discriminator 1))
> [ 275.004747] __kasan_slab_free (mm/kasan/common.c:271)
> [ 275.004782] kfree (mm/slub.c:4601 (discriminator 3) mm/slub.c:4749 (discriminator 3))
> [ 275.004810] free_fw_priv (drivers/base/firmware_loader/main.c:231)
> [ 275.004840] release_firmware (drivers/base/firmware_loader/main.c:604 drivers/base/firmware_loader/main.c:1170 drivers/base/firmware_loader/main.c:1166)
> [ 275.004871] lp55xx_firmware_loaded (drivers/leds/leds-lp55xx-common.c:549) leds_lp55xx_common
> [ 275.005074] request_firmware_work_func (drivers/base/firmware_loader/main.c:1197)
> [ 275.005112] process_one_work (kernel/workqueue.c:3235)
> [ 275.005145] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
> [ 275.005174] kthread (kernel/kthread.c:389)
> [ 275.005212] ret_from_fork (arch/arm/kernel/entry-common.S:138)
> [ 275.006754] The buggy address belongs to the object at b31d0800 which belongs to the cache kmalloc-128 of size 128
> [ 275.018610] The buggy address is located 80 bytes inside of freed 128-byte region [b31d0800, b31d0880)
> [ 275.030938] The buggy address belongs to the physical page:
> [ 275.036533] page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x131d0
> [ 275.036568] flags: 0x0(zone=0)
> [ 275.036598] page_type: f5(slab)
> [ 275.036634] raw: 00000000 b2001400 df9544e0 00000002 00000000 00100010 f5000000 00000001
> [ 275.036659] page dumped because: kasan: bad access detected
>
> [ 275.038189] Memory state around the buggy address:
> [ 275.043008] b31d0700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 275.049563] b31d0780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [ 275.056120] >b31d0800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 275.062669] ^
> [ 275.067831] b31d0880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [ 275.074386] b31d0900: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
> [ 275.080938] ==================================================================
>
> I couldn't find any related patches to fix this issue in upstream, so
> I have made the following patch to address this issue, but I have some concerns about it.
>
> Could someone please provide feedback or insights on this?
>
> ----
> drivers/base/firmware_loader/main.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
> index c6664a787..1a49022f4 100644
> --- a/drivers/base/firmware_loader/main.c
> +++ b/drivers/base/firmware_loader/main.c
> @@ -211,6 +211,7 @@ static void __free_fw_priv(struct kref *ref)
> (unsigned int)fw_priv->size);
>
> list_del(&fw_priv->list);
> + list_del(&fw_priv->pending_list);
References to &fw_priv->pending_list in this context would need to
be bounded with "#ifdef CONFIG_FW_LOADER_USER_HELPER".
Have you repeated your long-term stability test with this change?
- Russ
> spin_unlock(&fwc->lock);
>
> if (fw_is_paged_buf(fw_priv))
> ----
>
>
> Thanks a lot!
>
> Best regards,
> Andrei Lalaev
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: use-after-free in firmware_fallback_sysfs
2025-09-11 22:35 ` Russ Weight
@ 2025-09-12 10:13 ` Andrei Lalaev
2025-09-16 20:44 ` Russ Weight
0 siblings, 1 reply; 5+ messages in thread
From: Andrei Lalaev @ 2025-09-12 10:13 UTC (permalink / raw)
To: Russ Weight, Lalaev, Andrei
Cc: rafael@kernel.org, gregkh@linuxfoundation.org, dakr@kernel.org,
mcgrof@kernel.org, linux-kernel@vger.kernel.org,
linux-leds@vger.kernel.org
On 12.09.2025 00:35, Russ Weight wrote:
>
> On Thu, Sep 04, 2025 at 04:58:45AM +0000, Lalaev, Andrei wrote:
>> Hi,
>>
>> We performed a long-term stability test on the LP5562 driver by repeatedly
>> downloading different LED firmwares using sysfs interface.
>> And after some time, we see the following "use-after-free" trace on kernel 6.12.11:
>>
>> [ 274.759115] BUG: KASAN: slab-use-after-free in firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
>> [ 274.766743] Write of size 4 at addr b31d0850 by task kworker/2:2/137
>> [ 274.774680] CPU: 2 UID: 0 PID: 137 Comm: kworker/2:2 Tainted: G C 6.12.11 #1
>> [ 274.783208] Tainted: [C]=CRAP
>> [ 274.786215] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
>> [ 274.792775] Workqueue: events request_firmware_work_func
>> [ 274.798151] Call trace:
>> [ 274.800720] dump_backtrace from show_stack (arch/arm/kernel/traps.c:259)
>> [ 274.805827] r7:600f0093 r6:600f0093 r5:b19659b4 r4:00000000
>> [ 274.811510] show_stack from dump_stack_lvl (lib/dump_stack.c:122)
>> [ 274.816613] dump_stack_lvl from print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
>> [ 274.822073] r7:000031d0 r6:df7dba00 r5:f13bbb20 r4:b31d0850
>> [ 274.827755] print_report from kasan_report (mm/kasan/report.c:603)
>> [ 274.832885] r10:b2d56c20 r9:cdc89808 r8:00003a98 r7:b0f653ac r6:00000004 r5:00000001
>> [ 274.840744] r4:b31d0850
>> [ 274.843298] kasan_report from __asan_report_store4_noabort (mm/kasan/report_generic.c:385)
>> [ 274.849804] r7:b9f72c00 r6:cdc89800 r5:b5d31e00 r4:b5d31e10
>> [ 274.855488] __asan_report_store4_noabort from firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
>> [ 274.863105] firmware_fallback_sysfs from _request_firmware (drivers/base/firmware_loader/main.c:941)
>> [ 274.869862] r10:f13bbda0 r9:b9f72c80 r8:b19c73d8 r7:00000004 r6:00000000 r5:b5d31e00
>> [ 274.877718] r4:f13bbd00
>> [ 274.880273] _request_firmware from request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
>> [ 274.887226] r10:b9f72e98 r9:b9f72e94 r8:f13bbde0 r7:173ee5d3 r6:00000000 r5:ad2777b0
>> [ 274.895097] r4:b9f72e80
>> [ 274.897661] request_firmware_work_func from process_one_work (kernel/workqueue.c:3235)
>> [ 274.904613] r10:00000000 r9:b7d7e1e0 r8:b7d7dd80 r7:d76b53c0 r6:b2013c00 r5:b9f72e80
>> [ 274.912469] r4:b2371a00
>> [ 274.915024] process_one_work from worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
>> [ 274.920823] r10:b2371a2c r9:b2371a00 r8:b9f72e84 r7:b2371a2c r6:d76b53dc r5:a546e345
>> [ 274.928678] r4:00000007
>> [ 274.931234] worker_thread from kthread (kernel/kthread.c:389)
>> [ 274.936179] r10:f0933ca0 r9:b2371a00 r8:b7f6b800 r7:b019ad18 r6:b2354880 r5:b7d7dd80
>> [ 274.944035] r4:b2354d00
>> [ 274.946592] kthread from ret_from_fork (arch/arm/kernel/entry-common.S:138)
>> [ 274.951350] Exception stack(0xf13bbfb0 to 0xf13bbff8)
>> [ 274.956435] bfa0: 00000000 00000000 00000000 00000000
>> [ 274.964647] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
>> [ 274.972858] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
>> [ 274.979508] r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:b01ba280
>> [ 274.987365] r4:b2354d00 r3:00000000
>>
>> [ 274.992472] Allocated by task 8 on cpu 0 at 273.209883s:
>> [ 274.997814] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
>> [ 274.997858] kasan_save_alloc_info (mm/kasan/generic.c:566)
>> [ 274.997892] __kasan_kmalloc (mm/kasan/common.c:398)
>> [ 274.997926] __kmalloc_cache_noprof (mm/slub.c:4319)
>> [ 274.997957] alloc_lookup_fw_priv (drivers/base/firmware_loader/main.c:131 drivers/base/firmware_loader/main.c:190)
>> [ 274.997993] _request_firmware (drivers/base/firmware_loader/main.c:769 drivers/base/firmware_loader/main.c:899)
>> [ 274.998023] request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
>> [ 274.998055] process_one_work (kernel/workqueue.c:3235)
>> [ 274.998084] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
>> [ 274.998112] kthread (kernel/kthread.c:389)
>> [ 274.998149] ret_from_fork (arch/arm/kernel/entry-common.S:138)
>>
>> [ 274.999686] Freed by task 8 on cpu 0 at 273.230581s:
>> [ 275.004679] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
>> [ 275.004718] kasan_save_free_info (mm/kasan/generic.c:582 (discriminator 1))
>> [ 275.004747] __kasan_slab_free (mm/kasan/common.c:271)
>> [ 275.004782] kfree (mm/slub.c:4601 (discriminator 3) mm/slub.c:4749 (discriminator 3))
>> [ 275.004810] free_fw_priv (drivers/base/firmware_loader/main.c:231)
>> [ 275.004840] release_firmware (drivers/base/firmware_loader/main.c:604 drivers/base/firmware_loader/main.c:1170 drivers/base/firmware_loader/main.c:1166)
>> [ 275.004871] lp55xx_firmware_loaded (drivers/leds/leds-lp55xx-common.c:549) leds_lp55xx_common
>> [ 275.005074] request_firmware_work_func (drivers/base/firmware_loader/main.c:1197)
>> [ 275.005112] process_one_work (kernel/workqueue.c:3235)
>> [ 275.005145] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
>> [ 275.005174] kthread (kernel/kthread.c:389)
>> [ 275.005212] ret_from_fork (arch/arm/kernel/entry-common.S:138)
>> [ 275.006754] The buggy address belongs to the object at b31d0800 which belongs to the cache kmalloc-128 of size 128
>> [ 275.018610] The buggy address is located 80 bytes inside of freed 128-byte region [b31d0800, b31d0880)
>> [ 275.030938] The buggy address belongs to the physical page:
>> [ 275.036533] page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x131d0
>> [ 275.036568] flags: 0x0(zone=0)
>> [ 275.036598] page_type: f5(slab)
>> [ 275.036634] raw: 00000000 b2001400 df9544e0 00000002 00000000 00100010 f5000000 00000001
>> [ 275.036659] page dumped because: kasan: bad access detected
>>
>> [ 275.038189] Memory state around the buggy address:
>> [ 275.043008] b31d0700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> [ 275.049563] b31d0780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>> [ 275.056120] >b31d0800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> [ 275.062669] ^
>> [ 275.067831] b31d0880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>> [ 275.074386] b31d0900: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
>> [ 275.080938] ==================================================================
>>
>> I couldn't find any related patches to fix this issue in upstream, so
>> I have made the following patch to address this issue, but I have some concerns about it.
>>
>> Could someone please provide feedback or insights on this?
>>
>> ----
>> drivers/base/firmware_loader/main.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
>> index c6664a787..1a49022f4 100644
>> --- a/drivers/base/firmware_loader/main.c
>> +++ b/drivers/base/firmware_loader/main.c
>> @@ -211,6 +211,7 @@ static void __free_fw_priv(struct kref *ref)
>> (unsigned int)fw_priv->size);
>>
>> list_del(&fw_priv->list);
>> + list_del(&fw_priv->pending_list);
>
> References to &fw_priv->pending_list in this context would need to
> be bounded with "#ifdef CONFIG_FW_LOADER_USER_HELPER".
>
> Have you repeated your long-term stability test with this change?
>
Hi Russ,
Yes, sure. I had the test running for 2 days, and no "use-after-free" appeared.
--
Best regards,
Andrei Lalaev
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: use-after-free in firmware_fallback_sysfs
2025-09-12 10:13 ` Andrei Lalaev
@ 2025-09-16 20:44 ` Russ Weight
2025-09-17 18:28 ` Andrei Lalaev
0 siblings, 1 reply; 5+ messages in thread
From: Russ Weight @ 2025-09-16 20:44 UTC (permalink / raw)
To: Andrei Lalaev
Cc: Lalaev, Andrei, rafael@kernel.org, gregkh@linuxfoundation.org,
dakr@kernel.org, mcgrof@kernel.org, linux-kernel@vger.kernel.org,
linux-leds@vger.kernel.org
On Fri, Sep 12, 2025 at 12:13:30PM +0200, Andrei Lalaev wrote:
> On 12.09.2025 00:35, Russ Weight wrote:
> >
> > On Thu, Sep 04, 2025 at 04:58:45AM +0000, Lalaev, Andrei wrote:
> >> Hi,
> >>
> >> We performed a long-term stability test on the LP5562 driver by repeatedly
> >> downloading different LED firmwares using sysfs interface.
> >> And after some time, we see the following "use-after-free" trace on kernel 6.12.11:
> >>
> >> [ 274.759115] BUG: KASAN: slab-use-after-free in firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
> >> [ 274.766743] Write of size 4 at addr b31d0850 by task kworker/2:2/137
> >> [ 274.774680] CPU: 2 UID: 0 PID: 137 Comm: kworker/2:2 Tainted: G C 6.12.11 #1
> >> [ 274.783208] Tainted: [C]=CRAP
> >> [ 274.786215] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> >> [ 274.792775] Workqueue: events request_firmware_work_func
> >> [ 274.798151] Call trace:
> >> [ 274.800720] dump_backtrace from show_stack (arch/arm/kernel/traps.c:259)
> >> [ 274.805827] r7:600f0093 r6:600f0093 r5:b19659b4 r4:00000000
> >> [ 274.811510] show_stack from dump_stack_lvl (lib/dump_stack.c:122)
> >> [ 274.816613] dump_stack_lvl from print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
> >> [ 274.822073] r7:000031d0 r6:df7dba00 r5:f13bbb20 r4:b31d0850
> >> [ 274.827755] print_report from kasan_report (mm/kasan/report.c:603)
> >> [ 274.832885] r10:b2d56c20 r9:cdc89808 r8:00003a98 r7:b0f653ac r6:00000004 r5:00000001
> >> [ 274.840744] r4:b31d0850
> >> [ 274.843298] kasan_report from __asan_report_store4_noabort (mm/kasan/report_generic.c:385)
> >> [ 274.849804] r7:b9f72c00 r6:cdc89800 r5:b5d31e00 r4:b5d31e10
> >> [ 274.855488] __asan_report_store4_noabort from firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
> >> [ 274.863105] firmware_fallback_sysfs from _request_firmware (drivers/base/firmware_loader/main.c:941)
> >> [ 274.869862] r10:f13bbda0 r9:b9f72c80 r8:b19c73d8 r7:00000004 r6:00000000 r5:b5d31e00
> >> [ 274.877718] r4:f13bbd00
> >> [ 274.880273] _request_firmware from request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
> >> [ 274.887226] r10:b9f72e98 r9:b9f72e94 r8:f13bbde0 r7:173ee5d3 r6:00000000 r5:ad2777b0
> >> [ 274.895097] r4:b9f72e80
> >> [ 274.897661] request_firmware_work_func from process_one_work (kernel/workqueue.c:3235)
> >> [ 274.904613] r10:00000000 r9:b7d7e1e0 r8:b7d7dd80 r7:d76b53c0 r6:b2013c00 r5:b9f72e80
> >> [ 274.912469] r4:b2371a00
> >> [ 274.915024] process_one_work from worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
> >> [ 274.920823] r10:b2371a2c r9:b2371a00 r8:b9f72e84 r7:b2371a2c r6:d76b53dc r5:a546e345
> >> [ 274.928678] r4:00000007
> >> [ 274.931234] worker_thread from kthread (kernel/kthread.c:389)
> >> [ 274.936179] r10:f0933ca0 r9:b2371a00 r8:b7f6b800 r7:b019ad18 r6:b2354880 r5:b7d7dd80
> >> [ 274.944035] r4:b2354d00
> >> [ 274.946592] kthread from ret_from_fork (arch/arm/kernel/entry-common.S:138)
> >> [ 274.951350] Exception stack(0xf13bbfb0 to 0xf13bbff8)
> >> [ 274.956435] bfa0: 00000000 00000000 00000000 00000000
> >> [ 274.964647] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> >> [ 274.972858] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
> >> [ 274.979508] r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:b01ba280
> >> [ 274.987365] r4:b2354d00 r3:00000000
> >>
> >> [ 274.992472] Allocated by task 8 on cpu 0 at 273.209883s:
> >> [ 274.997814] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
> >> [ 274.997858] kasan_save_alloc_info (mm/kasan/generic.c:566)
> >> [ 274.997892] __kasan_kmalloc (mm/kasan/common.c:398)
> >> [ 274.997926] __kmalloc_cache_noprof (mm/slub.c:4319)
> >> [ 274.997957] alloc_lookup_fw_priv (drivers/base/firmware_loader/main.c:131 drivers/base/firmware_loader/main.c:190)
> >> [ 274.997993] _request_firmware (drivers/base/firmware_loader/main.c:769 drivers/base/firmware_loader/main.c:899)
> >> [ 274.998023] request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
> >> [ 274.998055] process_one_work (kernel/workqueue.c:3235)
> >> [ 274.998084] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
> >> [ 274.998112] kthread (kernel/kthread.c:389)
> >> [ 274.998149] ret_from_fork (arch/arm/kernel/entry-common.S:138)
> >>
> >> [ 274.999686] Freed by task 8 on cpu 0 at 273.230581s:
> >> [ 275.004679] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
> >> [ 275.004718] kasan_save_free_info (mm/kasan/generic.c:582 (discriminator 1))
> >> [ 275.004747] __kasan_slab_free (mm/kasan/common.c:271)
> >> [ 275.004782] kfree (mm/slub.c:4601 (discriminator 3) mm/slub.c:4749 (discriminator 3))
> >> [ 275.004810] free_fw_priv (drivers/base/firmware_loader/main.c:231)
> >> [ 275.004840] release_firmware (drivers/base/firmware_loader/main.c:604 drivers/base/firmware_loader/main.c:1170 drivers/base/firmware_loader/main.c:1166)
> >> [ 275.004871] lp55xx_firmware_loaded (drivers/leds/leds-lp55xx-common.c:549) leds_lp55xx_common
> >> [ 275.005074] request_firmware_work_func (drivers/base/firmware_loader/main.c:1197)
> >> [ 275.005112] process_one_work (kernel/workqueue.c:3235)
> >> [ 275.005145] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
> >> [ 275.005174] kthread (kernel/kthread.c:389)
> >> [ 275.005212] ret_from_fork (arch/arm/kernel/entry-common.S:138)
> >> [ 275.006754] The buggy address belongs to the object at b31d0800 which belongs to the cache kmalloc-128 of size 128
> >> [ 275.018610] The buggy address is located 80 bytes inside of freed 128-byte region [b31d0800, b31d0880)
> >> [ 275.030938] The buggy address belongs to the physical page:
> >> [ 275.036533] page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x131d0
> >> [ 275.036568] flags: 0x0(zone=0)
> >> [ 275.036598] page_type: f5(slab)
> >> [ 275.036634] raw: 00000000 b2001400 df9544e0 00000002 00000000 00100010 f5000000 00000001
> >> [ 275.036659] page dumped because: kasan: bad access detected
> >>
> >> [ 275.038189] Memory state around the buggy address:
> >> [ 275.043008] b31d0700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >> [ 275.049563] b31d0780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >> [ 275.056120] >b31d0800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >> [ 275.062669] ^
> >> [ 275.067831] b31d0880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >> [ 275.074386] b31d0900: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
> >> [ 275.080938] ==================================================================
> >>
> >> I couldn't find any related patches to fix this issue in upstream, so
> >> I have made the following patch to address this issue, but I have some concerns about it.
> >>
> >> Could someone please provide feedback or insights on this?
> >>
> >> ----
> >> drivers/base/firmware_loader/main.c | 1 +
> >> 1 file changed, 1 insertion(+)
> >>
> >> diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
> >> index c6664a787..1a49022f4 100644
> >> --- a/drivers/base/firmware_loader/main.c
> >> +++ b/drivers/base/firmware_loader/main.c
> >> @@ -211,6 +211,7 @@ static void __free_fw_priv(struct kref *ref)
> >> (unsigned int)fw_priv->size);
> >>
> >> list_del(&fw_priv->list);
> >> + list_del(&fw_priv->pending_list);
> >
> > References to &fw_priv->pending_list in this context would need to
> > be bounded with "#ifdef CONFIG_FW_LOADER_USER_HELPER".
> >
> > Have you repeated your long-term stability test with this change?
> >
>
> Hi Russ,
>
> Yes, sure. I had the test running for 2 days, and no "use-after-free" appeared.
>
Hi Andrei,
Have you looked at the firmware fallback selftests? These are at
tools/testing/selftests/firmware/fw_fallback.sh. I'm wondering if
these tests could be modified to expose the bug that you found. Can
you take a look?
Thanks,
- Russ
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: use-after-free in firmware_fallback_sysfs
2025-09-16 20:44 ` Russ Weight
@ 2025-09-17 18:28 ` Andrei Lalaev
0 siblings, 0 replies; 5+ messages in thread
From: Andrei Lalaev @ 2025-09-17 18:28 UTC (permalink / raw)
To: Russ Weight
Cc: Lalaev, Andrei, rafael@kernel.org, gregkh@linuxfoundation.org,
dakr@kernel.org, mcgrof@kernel.org, linux-kernel@vger.kernel.org,
linux-leds@vger.kernel.org
On 16.09.2025 22:44, Russ Weight wrote:
> On Fri, Sep 12, 2025 at 12:13:30PM +0200, Andrei Lalaev wrote:
>> On 12.09.2025 00:35, Russ Weight wrote:
>>>
>>> On Thu, Sep 04, 2025 at 04:58:45AM +0000, Lalaev, Andrei wrote:
>>>> Hi,
>>>>
>>>> We performed a long-term stability test on the LP5562 driver by repeatedly
>>>> downloading different LED firmwares using sysfs interface.
>>>> And after some time, we see the following "use-after-free" trace on kernel 6.12.11:
>>>>
>>>> [ 274.759115] BUG: KASAN: slab-use-after-free in firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
>>>> [ 274.766743] Write of size 4 at addr b31d0850 by task kworker/2:2/137
>>>> [ 274.774680] CPU: 2 UID: 0 PID: 137 Comm: kworker/2:2 Tainted: G C 6.12.11 #1
>>>> [ 274.783208] Tainted: [C]=CRAP
>>>> [ 274.786215] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
>>>> [ 274.792775] Workqueue: events request_firmware_work_func
>>>> [ 274.798151] Call trace:
>>>> [ 274.800720] dump_backtrace from show_stack (arch/arm/kernel/traps.c:259)
>>>> [ 274.805827] r7:600f0093 r6:600f0093 r5:b19659b4 r4:00000000
>>>> [ 274.811510] show_stack from dump_stack_lvl (lib/dump_stack.c:122)
>>>> [ 274.816613] dump_stack_lvl from print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
>>>> [ 274.822073] r7:000031d0 r6:df7dba00 r5:f13bbb20 r4:b31d0850
>>>> [ 274.827755] print_report from kasan_report (mm/kasan/report.c:603)
>>>> [ 274.832885] r10:b2d56c20 r9:cdc89808 r8:00003a98 r7:b0f653ac r6:00000004 r5:00000001
>>>> [ 274.840744] r4:b31d0850
>>>> [ 274.843298] kasan_report from __asan_report_store4_noabort (mm/kasan/report_generic.c:385)
>>>> [ 274.849804] r7:b9f72c00 r6:cdc89800 r5:b5d31e00 r4:b5d31e10
>>>> [ 274.855488] __asan_report_store4_noabort from firmware_fallback_sysfs (include/linux/list.h:153 include/linux/list.h:169 drivers/base/firmware_loader/fallback.c:98 drivers/base/firmware_loader/fallback.c:162 drivers/base/firmware_loader/fallback.c:238)
>>>> [ 274.863105] firmware_fallback_sysfs from _request_firmware (drivers/base/firmware_loader/main.c:941)
>>>> [ 274.869862] r10:f13bbda0 r9:b9f72c80 r8:b19c73d8 r7:00000004 r6:00000000 r5:b5d31e00
>>>> [ 274.877718] r4:f13bbd00
>>>> [ 274.880273] _request_firmware from request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
>>>> [ 274.887226] r10:b9f72e98 r9:b9f72e94 r8:f13bbde0 r7:173ee5d3 r6:00000000 r5:ad2777b0
>>>> [ 274.895097] r4:b9f72e80
>>>> [ 274.897661] request_firmware_work_func from process_one_work (kernel/workqueue.c:3235)
>>>> [ 274.904613] r10:00000000 r9:b7d7e1e0 r8:b7d7dd80 r7:d76b53c0 r6:b2013c00 r5:b9f72e80
>>>> [ 274.912469] r4:b2371a00
>>>> [ 274.915024] process_one_work from worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
>>>> [ 274.920823] r10:b2371a2c r9:b2371a00 r8:b9f72e84 r7:b2371a2c r6:d76b53dc r5:a546e345
>>>> [ 274.928678] r4:00000007
>>>> [ 274.931234] worker_thread from kthread (kernel/kthread.c:389)
>>>> [ 274.936179] r10:f0933ca0 r9:b2371a00 r8:b7f6b800 r7:b019ad18 r6:b2354880 r5:b7d7dd80
>>>> [ 274.944035] r4:b2354d00
>>>> [ 274.946592] kthread from ret_from_fork (arch/arm/kernel/entry-common.S:138)
>>>> [ 274.951350] Exception stack(0xf13bbfb0 to 0xf13bbff8)
>>>> [ 274.956435] bfa0: 00000000 00000000 00000000 00000000
>>>> [ 274.964647] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
>>>> [ 274.972858] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
>>>> [ 274.979508] r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:b01ba280
>>>> [ 274.987365] r4:b2354d00 r3:00000000
>>>>
>>>> [ 274.992472] Allocated by task 8 on cpu 0 at 273.209883s:
>>>> [ 274.997814] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
>>>> [ 274.997858] kasan_save_alloc_info (mm/kasan/generic.c:566)
>>>> [ 274.997892] __kasan_kmalloc (mm/kasan/common.c:398)
>>>> [ 274.997926] __kmalloc_cache_noprof (mm/slub.c:4319)
>>>> [ 274.997957] alloc_lookup_fw_priv (drivers/base/firmware_loader/main.c:131 drivers/base/firmware_loader/main.c:190)
>>>> [ 274.997993] _request_firmware (drivers/base/firmware_loader/main.c:769 drivers/base/firmware_loader/main.c:899)
>>>> [ 274.998023] request_firmware_work_func (drivers/base/firmware_loader/main.c:1196)
>>>> [ 274.998055] process_one_work (kernel/workqueue.c:3235)
>>>> [ 274.998084] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
>>>> [ 274.998112] kthread (kernel/kthread.c:389)
>>>> [ 274.998149] ret_from_fork (arch/arm/kernel/entry-common.S:138)
>>>>
>>>> [ 274.999686] Freed by task 8 on cpu 0 at 273.230581s:
>>>> [ 275.004679] kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
>>>> [ 275.004718] kasan_save_free_info (mm/kasan/generic.c:582 (discriminator 1))
>>>> [ 275.004747] __kasan_slab_free (mm/kasan/common.c:271)
>>>> [ 275.004782] kfree (mm/slub.c:4601 (discriminator 3) mm/slub.c:4749 (discriminator 3))
>>>> [ 275.004810] free_fw_priv (drivers/base/firmware_loader/main.c:231)
>>>> [ 275.004840] release_firmware (drivers/base/firmware_loader/main.c:604 drivers/base/firmware_loader/main.c:1170 drivers/base/firmware_loader/main.c:1166)
>>>> [ 275.004871] lp55xx_firmware_loaded (drivers/leds/leds-lp55xx-common.c:549) leds_lp55xx_common
>>>> [ 275.005074] request_firmware_work_func (drivers/base/firmware_loader/main.c:1197)
>>>> [ 275.005112] process_one_work (kernel/workqueue.c:3235)
>>>> [ 275.005145] worker_thread (kernel/workqueue.c:3304 (discriminator 2) kernel/workqueue.c:3391 (discriminator 2))
>>>> [ 275.005174] kthread (kernel/kthread.c:389)
>>>> [ 275.005212] ret_from_fork (arch/arm/kernel/entry-common.S:138)
>>>> [ 275.006754] The buggy address belongs to the object at b31d0800 which belongs to the cache kmalloc-128 of size 128
>>>> [ 275.018610] The buggy address is located 80 bytes inside of freed 128-byte region [b31d0800, b31d0880)
>>>> [ 275.030938] The buggy address belongs to the physical page:
>>>> [ 275.036533] page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x131d0
>>>> [ 275.036568] flags: 0x0(zone=0)
>>>> [ 275.036598] page_type: f5(slab)
>>>> [ 275.036634] raw: 00000000 b2001400 df9544e0 00000002 00000000 00100010 f5000000 00000001
>>>> [ 275.036659] page dumped because: kasan: bad access detected
>>>>
>>>> [ 275.038189] Memory state around the buggy address:
>>>> [ 275.043008] b31d0700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>>> [ 275.049563] b31d0780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>>> [ 275.056120] >b31d0800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>>> [ 275.062669] ^
>>>> [ 275.067831] b31d0880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>>> [ 275.074386] b31d0900: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
>>>> [ 275.080938] ==================================================================
>>>>
>>>> I couldn't find any related patches to fix this issue in upstream, so
>>>> I have made the following patch to address this issue, but I have some concerns about it.
>>>>
>>>> Could someone please provide feedback or insights on this?
>>>>
>>>> ----
>>>> drivers/base/firmware_loader/main.c | 1 +
>>>> 1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
>>>> index c6664a787..1a49022f4 100644
>>>> --- a/drivers/base/firmware_loader/main.c
>>>> +++ b/drivers/base/firmware_loader/main.c
>>>> @@ -211,6 +211,7 @@ static void __free_fw_priv(struct kref *ref)
>>>> (unsigned int)fw_priv->size);
>>>>
>>>> list_del(&fw_priv->list);
>>>> + list_del(&fw_priv->pending_list);
>>>
>>> References to &fw_priv->pending_list in this context would need to
>>> be bounded with "#ifdef CONFIG_FW_LOADER_USER_HELPER".
>>>
>>> Have you repeated your long-term stability test with this change?
>>>
>>
>> Hi Russ,
>>
>> Yes, sure. I had the test running for 2 days, and no "use-after-free" appeared.
>>
>
> Hi Andrei,
>
> Have you looked at the firmware fallback selftests? These are at
> tools/testing/selftests/firmware/fw_fallback.sh. I'm wondering if
> these tests could be modified to expose the bug that you found. Can
> you take a look?
Hm, I didn't know about them. Will take a look then.
Thanks for the hint!
--
Best regards,
Andrei Lalaev
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2025-09-17 18:28 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2025-09-04 4:58 use-after-free in firmware_fallback_sysfs Lalaev, Andrei
2025-09-11 22:35 ` Russ Weight
2025-09-12 10:13 ` Andrei Lalaev
2025-09-16 20:44 ` Russ Weight
2025-09-17 18:28 ` Andrei Lalaev
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