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KASAN: use-after-free Read in lock_get_status (2)

Status: premoderation: reported on 2025/06/04 08:57
Reported-by: syzbot+02b32c55241f36fc7b0b@syzkaller.appspotmail.com
First crash: 4d17h, last: 4d17h
▶ ▼ Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 KASAN: use-after-free Read in lock_get_status 4 176d 193d 0/2 auto-obsoleted due to no activity on 2025/03/14 06:31

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in file_inode include/linux/fs.h:1343 [inline]
BUG: KASAN: use-after-free in lock_get_status+0x206/0x960 fs/locks.c:2861
Read of size 8 at addr ffff88811a885b20 by task syz.4.4973/17402

CPU: 0 PID: 17402 Comm: syz.4.4973 Not tainted 5.10.237-syzkaller-00010-gcf6ed0f1511d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 file_inode include/linux/fs.h:1343 [inline]
 lock_get_status+0x206/0x960 fs/locks.c:2861
 locks_show+0x1f1/0x2f0 fs/locks.c:2936
 traverse+0x1d1/0x510 fs/seq_file.c:111
 seq_read_iter+0xc57/0xd30 fs/seq_file.c:195
 proc_reg_read_iter+0x1be/0x290 fs/proc/inode.c:310
 call_read_iter include/linux/fs.h:2052 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x874/0xa10 fs/read_write.c:496
 ksys_pread64 fs/read_write.c:686 [inline]
 __do_sys_pread64 fs/read_write.c:696 [inline]
 __se_sys_pread64 fs/read_write.c:693 [inline]
 __x64_sys_pread64+0x191/0x220 fs/read_write.c:693
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f9d32f09969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9d31572038 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007f9d33130fa0 RCX: 00007f9d32f09969
RDX: 000000000000008b RSI: 0000200000000a00 RDI: 0000000000000005
RBP: 00007f9d32f8bab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f9d33130fa0 R15: 00007ffd5b064328

Allocated by task 17158:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:463
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:583
 slab_alloc_node mm/slub.c:2947 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2960
 kmem_cache_zalloc include/linux/slab.h:654 [inline]
 __alloc_file+0x28/0x320 fs/file_table.c:101
 alloc_empty_file+0x97/0x180 fs/file_table.c:151
 path_openat+0xf2/0x3160 fs/namei.c:3495
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3536
 do_sys_openat2+0x14c/0x6d0 fs/open.c:1217
 do_sys_open fs/open.c:1233 [inline]
 __do_sys_openat fs/open.c:1249 [inline]
 __se_sys_openat fs/open.c:1244 [inline]
 __x64_sys_openat+0x136/0x160 fs/open.c:1244
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 17164:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1595 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621
 slab_free mm/slub.c:3203 [inline]
 kmem_cache_free+0x100/0x2d0 mm/slub.c:3219
 file_free_rcu+0x93/0xa0 fs/file_table.c:50
 rcu_do_batch+0x4df/0xa80 kernel/rcu/tree.c:2494
 rcu_core+0x55f/0xd60 kernel/rcu/tree.c:2735
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2748
 __do_softirq+0x255/0x563 kernel/softirq.c:309

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 __call_rcu kernel/rcu/tree.c:2976 [inline]
 call_rcu+0x105/0x1040 kernel/rcu/tree.c:3050
 file_free fs/file_table.c:58 [inline]
 __fput+0x5ad/0x770 fs/file_table.c:299
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x127/0x190 kernel/task_work.c:189
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172
 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline]
 syscall_exit_to_user_mode+0x68/0x90 kernel/entry/common.c:274
 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack+0xe/0x10 mm/kasan/generic.c:353
 task_work_add+0x27/0x1e0 kernel/task_work.c:38
 fput_many+0xe7/0x1a0 fs/file_table.c:342
 fput+0x1a/0x20 fs/file_table.c:358
 path_openat+0x2b36/0x3160 fs/namei.c:3518
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3536
 do_sys_openat2+0x14c/0x6d0 fs/open.c:1217
 do_sys_open fs/open.c:1233 [inline]
 __do_sys_openat fs/open.c:1249 [inline]
 __se_sys_openat fs/open.c:1244 [inline]
 __x64_sys_openat+0x136/0x160 fs/open.c:1244
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff88811a885b00
 which belongs to the cache filp of size 296
The buggy address is located 32 bytes inside of
 296-byte region [ffff88811a885b00, ffff88811a885c28)
The buggy address belongs to the page:
page:ffffea00046a2100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11a884
head:ffffea00046a2100 order:1 compound_mapcount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 ffffea0004836400 0000000200000002 ffff88810018bb00
raw: 0000000000000000 0000000000150015 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 11492, ts 809905933843, free_ts 809324002332
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5349
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1808 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1869
 new_slab_objects mm/slub.c:2627 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2791
 __slab_alloc+0x63/0xa0 mm/slub.c:2831
 slab_alloc_node mm/slub.c:2913 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x1af/0x2e0 mm/slub.c:2960
 kmem_cache_zalloc include/linux/slab.h:654 [inline]
 __alloc_file+0x28/0x320 fs/file_table.c:101
 alloc_empty_file+0x97/0x180 fs/file_table.c:151
 path_openat+0xf2/0x3160 fs/namei.c:3495
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3536
 do_sys_openat2+0x14c/0x6d0 fs/open.c:1217
 do_sys_open fs/open.c:1233 [inline]
 __do_sys_openat fs/open.c:1249 [inline]
 __se_sys_openat fs/open.c:1244 [inline]
 __x64_sys_openat+0x136/0x160 fs/open.c:1244
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x12e/0x9b0 mm/page_alloc.c:3443
 release_pages+0xe38/0xe80 mm/swap.c:1103
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:356
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x175/0x300 mm/mmu_gather.c:326
 exit_mmap+0x2fc/0x540 mm/mmap.c:3375
 __mmput+0x93/0x2f0 kernel/fork.c:1153
 mmput+0x4e/0x150 kernel/fork.c:1176
 exit_mm kernel/exit.c:539 [inline]
 do_exit+0x986/0x2470 kernel/exit.c:850
 __do_sys_exit kernel/exit.c:954 [inline]
 __se_sys_exit kernel/exit.c:952 [inline]
 __ia32_sys_exit+0x0/0x40 kernel/exit.c:952
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
 ffff88811a885a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811a885a80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
>ffff88811a885b00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88811a885b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811a885c00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/04 08:56 android13-5.10-lts cf6ed0f1511d a30356b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in lock_get_status
* Struck through repros no longer work on HEAD.