syzbot


KASAN: slab-use-after-free Read in vb2_fop_release

Status: upstream: reported on 2025/10/30 15:19
Subsystems: media
[Documentation on labels]
Reported-by: syzbot+c1d7d93187451574fbcf@syzkaller.appspotmail.com
First crash: 58d, last: 9d19h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [media?] KASAN: slab-use-after-free Read in vb2_fop_release 0 (1) 2025/10/30 15:19

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in _vb2_fop_release drivers/media/common/videobuf2/videobuf2-v4l2.c:1158 [inline]
BUG: KASAN: slab-use-after-free in vb2_fop_release+0xf0/0x200 drivers/media/common/videobuf2/videobuf2-v4l2.c:1173
Read of size 8 at addr ffff88807c128568 by task v4l_id/32563

CPU: 0 UID: 0 PID: 32563 Comm: v4l_id Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 _vb2_fop_release drivers/media/common/videobuf2/videobuf2-v4l2.c:1158 [inline]
 vb2_fop_release+0xf0/0x200 drivers/media/common/videobuf2/videobuf2-v4l2.c:1173
 v4l2_release+0x250/0x370 drivers/media/v4l2-core/v4l2-dev.c:471
 __fput+0x44c/0xa70 fs/file_table.c:468
 fput_close_sync+0x113/0x220 fs/file_table.c:573
 __do_sys_close fs/open.c:1573 [inline]
 __se_sys_close fs/open.c:1558 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1558
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fded7ca7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fffed4534c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007fded83c7880 RCX: 00007fded7ca7407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fded83c76e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
R13: 00007fffed4536f0 R14: 00007fded852e000 R15: 000055c4586174d8
 </TASK>

Allocated by task 24849:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5776
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 hackrf_probe+0xda/0x1390 drivers/media/usb/hackrf/hackrf.c:1351
 usb_probe_interface+0x668/0xc90 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26d/0xad0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:831
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:500
 __device_attach+0x2b8/0x430 drivers/base/dd.c:1031
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1086
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
 device_add+0x7b6/0xb80 drivers/base/core.c:3689
 usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2210
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c4/0x3c0 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26d/0xad0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:831
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:500
 __device_attach+0x2b8/0x430 drivers/base/dd.c:1031
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1086
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
 device_add+0x7b6/0xb80 drivers/base/core.c:3689
 usb_new_device+0xa39/0x1720 drivers/usb/core/hub.c:2695
 hub_port_connect drivers/usb/core/hub.c:5567 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x29b1/0x4ef0 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Freed by task 24849:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6668 [inline]
 kfree+0x1c0/0x660 mm/slub.c:6876
 hackrf_probe+0xd98/0x1390 drivers/media/usb/hackrf/hackrf.c:1523
 usb_probe_interface+0x668/0xc90 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26d/0xad0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:831
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:500
 __device_attach+0x2b8/0x430 drivers/base/dd.c:1031
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1086
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
 device_add+0x7b6/0xb80 drivers/base/core.c:3689
 usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2210
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c4/0x3c0 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26d/0xad0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:831
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:500
 __device_attach+0x2b8/0x430 drivers/base/dd.c:1031
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1086
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
 device_add+0x7b6/0xb80 drivers/base/core.c:3689
 usb_new_device+0xa39/0x1720 drivers/usb/core/hub.c:2695
 hub_port_connect drivers/usb/core/hub.c:5567 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x29b1/0x4ef0 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

The buggy address belongs to the object at ffff88807c128000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 1384 bytes inside of
 freed 8192-byte region [ffff88807c128000, ffff88807c12a000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7c128
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ffa7280 ffffea0001620400 0000000000000003
raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa7280 ffffea0001620400 0000000000000003
head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001f04a01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 32159, tgid 32158 (syz.4.8354), ts 1822140066340, free_ts 1822120065859
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
 prep_new_page mm/page_alloc.c:1854 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xf2b/0x1960 mm/slub.c:4656
 __slab_alloc+0x65/0x100 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __kmalloc_cache_noprof+0x41e/0x700 mm/slub.c:5771
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 tipc_mon_create+0xc2/0x490 net/tipc/monitor.c:657
 tipc_enable_bearer net/tipc/bearer.c:357 [inline]
 __tipc_nl_bearer_enable+0xe16/0x13f0 net/tipc/bearer.c:1047
 __tipc_nl_compat_doit net/tipc/netlink_compat.c:371 [inline]
 tipc_nl_compat_doit+0x3bc/0x5f0 net/tipc/netlink_compat.c:393
 tipc_nl_compat_handle net/tipc/netlink_compat.c:-1 [inline]
 tipc_nl_compat_recv+0x83c/0xbe0 net/tipc/netlink_compat.c:1321
 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
page last free pid 29090 tgid 29090 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
 __slab_free+0x21b/0x2a0 mm/slub.c:6004
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:349
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
 ptlock_alloc+0x20/0x70 mm/memory.c:7377
 ptlock_init include/linux/mm.h:3280 [inline]
 pagetable_pte_ctor include/linux/mm.h:3334 [inline]
 __pte_alloc_one_noprof include/asm-generic/pgalloc.h:79 [inline]
 pte_alloc_one+0x7a/0x370 arch/x86/mm/pgtable.c:18
 __pte_alloc+0x25/0x1a0 mm/memory.c:453
 copy_pte_range mm/memory.c:1237 [inline]
 copy_pmd_range+0x76cc/0x7e00 mm/memory.c:1392
 copy_pud_range mm/memory.c:1429 [inline]
 copy_p4d_range mm/memory.c:1453 [inline]
 copy_page_range+0xb88/0x11d0 mm/memory.c:1535
 dup_mmap+0xf4a/0x1b80 mm/mmap.c:1827
 dup_mm kernel/fork.c:1529 [inline]
 copy_mm+0x13c/0x4b0 kernel/fork.c:1581
 copy_process+0x165d/0x3950 kernel/fork.c:2221
 kernel_clone+0x21e/0x820 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776

Memory state around the buggy address:
 ffff88807c128400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807c128480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807c128500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff88807c128580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807c128600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/13 10:41 upstream 9551a26f17d9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in vb2_fop_release
2025/10/25 13:05 upstream 566771afc7a8 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in vb2_fop_release
* Struck through repros no longer work on HEAD.