syzbot


KASAN: slab-use-after-free Read in load_firmware_cb (2)

Status: upstream: reported C repro on 2025/03/30 07:21
Subsystems: usb media
[Documentation on labels]
Reported-by: syzbot+db4326df1b9af04f68fc@syzkaller.appspotmail.com
First crash: 100d, last: 4d05h
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly media report (Jun 2025) 0 (1) 2025/06/24 13:52
[syzbot] [media?] [usb?] KASAN: slab-use-after-free Read in load_firmware_cb (2) 0 (1) 2025/03/30 07:21
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in load_firmware_cb media 4 282d 337d 0/29 auto-obsoleted due to no activity on 2024/12/23 23:36
upstream KASAN: use-after-free Read in load_firmware_cb usb media C 12 1038d 1954d 0/29 auto-obsoleted due to no activity on 2023/11/09 13:12
linux-6.1 KASAN: use-after-free Read in load_firmware_cb 2 336d 337d 0/3 auto-obsoleted due to no activity on 2024/11/10 09:01
Last patch testing requests (6)
Created Duration User Patch Repo Result
2025/06/30 08:45 35m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/06/30 08:45 22m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/06/30 08:45 19m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/04/12 07:36 19m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/04/12 07:36 22m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/04/04 04:07 29m hdanton@sina.com patch git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci OK log

Sample crash report:
kobject: kobject_add_internal failed for firmware (error: -2 parent: 1-1:0.0)
firmware xc3028-v27.fw: fw_load_sysfs_fallback: device_register failed
==================================================================
BUG: KASAN: slab-use-after-free in load_firmware_cb+0xbc/0x14f4 drivers/media/tuners/xc2028.c:1372
Read of size 8 at addr ffff0000d4af9318 by task kworker/0:3/6522

CPU: 0 UID: 0 PID: 6522 Comm: kworker/0:3 Not tainted 6.16.0-rc1-syzkaller-g39dfc971e42d #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events request_firmware_work_func
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xa8/0x254 mm/kasan/report.c:408
 print_report+0x68/0x84 mm/kasan/report.c:521
 kasan_report+0xb0/0x110 mm/kasan/report.c:634
 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
 load_firmware_cb+0xbc/0x14f4 drivers/media/tuners/xc2028.c:1372
 request_firmware_work_func+0xe8/0x19c drivers/base/firmware_loader/main.c:1170
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847

Allocated by task 6522:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x2a4/0x3fc mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 tuner_probe+0xc4/0x1690 drivers/media/v4l2-core/tuner-core.c:636
 i2c_device_probe+0x864/0x9d0 drivers/i2c/i2c-core-base.c:591
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x394/0x910 drivers/base/dd.c:657
 __driver_probe_device+0x180/0x2d4 drivers/base/dd.c:799
 driver_probe_device+0x78/0x330 drivers/base/dd.c:829
 __device_attach_driver+0x290/0x4e0 drivers/base/dd.c:957
 bus_for_each_drv+0x220/0x2b4 drivers/base/bus.c:462
 __device_attach+0x26c/0x388 drivers/base/dd.c:1029
 device_initial_probe+0x24/0x34 drivers/base/dd.c:1078
 bus_probe_device+0x178/0x240 drivers/base/bus.c:537
 device_add+0x71c/0xa60 drivers/base/core.c:3692
 device_register+0x28/0x38 drivers/base/core.c:3774
 i2c_new_client_device+0x834/0xe9c drivers/i2c/i2c-core-base.c:1022
 v4l2_i2c_new_subdev_board+0xb0/0x224 drivers/media/v4l2-core/v4l2-i2c.c:80
 v4l2_i2c_new_subdev+0x138/0x1c0 drivers/media/v4l2-core/v4l2-i2c.c:135
 em28xx_v4l2_init+0x6f4/0x2918 drivers/media/usb/em28xx/em28xx-video.c:2617
 em28xx_init_extension+0x10c/0x1b4 drivers/media/usb/em28xx/em28xx-core.c:1117
 request_module_async+0x68/0x98 drivers/media/usb/em28xx/em28xx-cards.c:3457
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847

Freed by task 6522:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x68/0x88 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x17c/0x474 mm/slub.c:4842
 tuner_remove+0x1d8/0x1f4 drivers/media/v4l2-core/tuner-core.c:789
 i2c_device_remove+0x8c/0x1dc drivers/i2c/i2c-core-base.c:632
 device_remove drivers/base/dd.c:567 [inline]
 __device_release_driver drivers/base/dd.c:1272 [inline]
 device_release_driver_internal+0x3a8/0x658 drivers/base/dd.c:1295
 device_release_driver+0x28/0x38 drivers/base/dd.c:1318
 bus_remove_device+0x310/0x3b0 drivers/base/bus.c:579
 device_del+0x47c/0x808 drivers/base/core.c:3881
 device_unregister+0x2c/0xcc drivers/base/core.c:3922
 i2c_unregister_device+0x1a4/0x200 drivers/i2c/i2c-core-base.c:1072
 v4l2_i2c_subdev_unregister+0xa8/0xbc drivers/media/v4l2-core/v4l2-i2c.c:28
 v4l2_device_unregister+0x170/0x248 drivers/media/v4l2-core/v4l2-device.c:102
 em28xx_v4l2_init+0x1328/0x2918 drivers/media/usb/em28xx/em28xx-video.c:2898
 em28xx_init_extension+0x10c/0x1b4 drivers/media/usb/em28xx/em28xx-core.c:1117
 request_module_async+0x68/0x98 drivers/media/usb/em28xx/em28xx-cards.c:3457
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847

The buggy address belongs to the object at ffff0000d4af9000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 792 bytes inside of
 freed 2048-byte region [ffff0000d4af9000, ffff0000d4af9800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x114af8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000040 ffff0000c0002000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 05ffc00000000040 ffff0000c0002000 dead000000000122 0000000000000000
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 05ffc00000000003 fffffdffc352be01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d4af9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d4af9280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d4af9300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff0000d4af9380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d4af9400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Unable to handle kernel paging request at virtual address dfff800000000005
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000005] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 6522 Comm: kworker/0:3 Tainted: G    B               6.16.0-rc1-syzkaller-g39dfc971e42d #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events request_firmware_work_func
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : load_firmware_cb+0x22c/0x14f4 drivers/media/tuners/xc2028.c:1376
lr : load_firmware_cb+0xe0/0x14f4 drivers/media/tuners/xc2028.c:1374
sp : ffff80009d177880
x29: ffff80009d1779d0 x28: 1ffff00011ec629b x27: 0000000000000000
x26: dfff800000000000 x25: ffff700013a2ef24 x24: 1fffe0001a95f263
x23: ffff80009d177920 x22: 0000000000000000 x21: 0000000000000000
x20: 0000000000000000 x19: ffff0000d4af9318 x18: 00000000ffffffff
x17: 0000000000000000 x16: ffff80008ae31308 x15: 0000000000000001
x14: 1ffff000125d08f8 x13: 0000000000000000 x12: 0000000000000000
x11: ffff7000125d08f9 x10: 0000000000ff0100 x9 : 0000000000000000
x8 : 0000000000000005 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80009d1770f8 x4 : ffff80008f727060 x3 : ffff8000803b88c8
x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000028
Call trace:
 load_firmware_cb+0x22c/0x14f4 drivers/media/tuners/xc2028.c:1376 (P)
 request_firmware_work_func+0xe8/0x19c drivers/base/firmware_loader/main.c:1170
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847
Code: b5fff65b f9403bf6 9100a2c0 d343fc08 (387a6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	b5fff65b 	cbnz	x27, 0xfffffffffffffec8
   4:	f9403bf6 	ldr	x22, [sp, #112]
   8:	9100a2c0 	add	x0, x22, #0x28
   c:	d343fc08 	lsr	x8, x0, #3
* 10:	387a6908 	ldrb	w8, [x8, x26] <-- trapping instruction

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/16 02:53 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 39dfc971e42d 5f4b362d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Read in load_firmware_cb
2025/03/29 07:32 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a2392f333575 cf25e2c2 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Read in load_firmware_cb
2025/03/26 07:13 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a2392f333575 89d30d73 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Read in load_firmware_cb
* Struck through repros no longer work on HEAD.