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KASAN: slab-use-after-free Read in xfs_buf_rele (4)

Status: moderation: reported on 2025/08/09 07:13
Subsystems: xfs
[Documentation on labels]
Reported-by: syzbot+74c72ede6372ee77d40e@syzkaller.appspotmail.com
First crash: 20d, last: 11h26m
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in xfs_buf_rele xfs 19 2 438d 465d 0/29 auto-obsoleted due to no activity on 2024/09/11 19:16
upstream KASAN: slab-use-after-free Read in xfs_buf_rele (2) xfs 19 1 269d 259d 0/29 auto-obsoleted due to no activity on 2025/03/09 11:53
upstream KASAN: slab-use-after-free Read in xfs_buf_rele (3) xfs 19 1 120d 116d 0/29 auto-obsoleted due to no activity on 2025/07/27 00:40
linux-4.14 KASAN: use-after-free Read in xfs_buf_rele xfs 19 C 1 906d 976d 0/1 upstream: reported C repro on 2022/12/24 01:04
linux-4.19 KASAN: use-after-free Read in xfs_buf_rele 19 syz error 3 904d 985d 0/1 upstream: reported syz repro on 2022/12/14 21:15

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in rht_key_hashfn include/linux/rhashtable.h:159 [inline]
BUG: KASAN: slab-use-after-free in rht_head_hashfn include/linux/rhashtable.h:174 [inline]
BUG: KASAN: slab-use-after-free in __rhashtable_remove_fast_one include/linux/rhashtable.h:1007 [inline]
BUG: KASAN: slab-use-after-free in __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
BUG: KASAN: slab-use-after-free in rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
BUG: KASAN: slab-use-after-free in xfs_buf_rele_cached fs/xfs/xfs_buf.c:926 [inline]
BUG: KASAN: slab-use-after-free in xfs_buf_rele+0x977/0x1030 fs/xfs/xfs_buf.c:951
Read of size 4 at addr ffff888034aeec08 by task syz.5.244/7473

CPU: 0 UID: 0 PID: 7473 Comm: syz.5.244 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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
 rht_key_hashfn include/linux/rhashtable.h:159 [inline]
 rht_head_hashfn include/linux/rhashtable.h:174 [inline]
 __rhashtable_remove_fast_one include/linux/rhashtable.h:1007 [inline]
 __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
 rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
 xfs_buf_rele_cached fs/xfs/xfs_buf.c:926 [inline]
 xfs_buf_rele+0x977/0x1030 fs/xfs/xfs_buf.c:951
 xfs_buftarg_shrink_scan+0x23e/0x2d0 fs/xfs/xfs_buf.c:1653
 do_shrink_slab+0x6ec/0x1110 mm/shrinker.c:437
 shrink_slab+0xd74/0x10d0 mm/shrinker.c:664
 drop_slab_node mm/vmscan.c:441 [inline]
 drop_slab+0x14e/0x290 mm/vmscan.c:459
 drop_caches_sysctl_handler+0xc7/0x170 fs/drop_caches.c:68
 proc_sys_call_handler+0x4c4/0x700 fs/proc/proc_sysctl.c:600
 do_iter_readv_writev+0x62e/0x8d0 fs/read_write.c:-1
 vfs_writev+0x323/0x970 fs/read_write.c:1057
 do_writev+0x153/0x2d0 fs/read_write.c:1103
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffbfd8debe9
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:00007ffbfbb46038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007ffbfdb05fa0 RCX: 00007ffbfd8debe9
RDX: 0000000000000001 RSI: 0000200000020f80 RDI: 0000000000000009
RBP: 00007ffbfd961e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffbfdb06038 R14: 00007ffbfdb05fa0 R15: 00007fffc25febf8
 </TASK>

Allocated by task 7451:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4365 [inline]
 __kvmalloc_node_noprof+0x28d/0x550 mm/slub.c:5052
 bucket_table_alloc lib/rhashtable.c:186 [inline]
 rhashtable_init_noprof+0x501/0xbc0 lib/rhashtable.c:1075
 xfs_perag_alloc fs/xfs/libxfs/xfs_ag.c:238 [inline]
 xfs_initialize_perag+0x284/0x630 fs/xfs/libxfs/xfs_ag.c:279
 xfs_mountfs+0xae0/0x2330 fs/xfs/xfs_mount.c:995
 xfs_fs_fill_super+0x1185/0x15d0 fs/xfs/xfs_super.c:1965
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692
 vfs_get_tree+0x92/0x2b0 fs/super.c:1815
 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 7451:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kfree+0x195/0x550 mm/slub.c:4879
 rhashtable_free_and_destroy+0x7e8/0x940 lib/rhashtable.c:1173
 xfs_group_free+0x166/0x370 fs/xfs/libxfs/xfs_group.c:171
 xfs_free_perag_range+0x36/0x60 fs/xfs/libxfs/xfs_ag.c:133
 xfs_mountfs+0x1445/0x2330 fs/xfs/xfs_mount.c:1288
 xfs_fs_fill_super+0x1185/0x15d0 fs/xfs/xfs_super.c:1965
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692
 vfs_get_tree+0x92/0x2b0 fs/super.c:1815
 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888034aeec00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 freed 512-byte region [ffff888034aeec00, ffff888034aeee00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34aec
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff888019841c80 ffffea00017a8100 dead000000000003
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff888019841c80 ffffea00017a8100 dead000000000003
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000002 ffffea0000d2bb01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5209, tgid 5209 (udevd), ts 54067841326, free_ts 45697526205
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2487 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2655
 new_slab mm/slub.c:2709 [inline]
 ___slab_alloc+0x8d1/0xdd0 mm/slub.c:3891
 __slab_alloc mm/slub.c:3981 [inline]
 __slab_alloc_node mm/slub.c:4056 [inline]
 slab_alloc_node mm/slub.c:4217 [inline]
 __kmalloc_cache_noprof+0xe6/0x320 mm/slub.c:4391
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 kernfs_fop_open+0x3f0/0xdd0 fs/kernfs/file.c:623
 do_dentry_open+0x9ae/0x1350 fs/open.c:965
 vfs_open+0x3b/0x350 fs/open.c:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x2ef1/0x3840 fs/namei.c:4046
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1461
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5213 tgid 5213 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xb59/0xce0 mm/page_alloc.c:2895
 __slab_free+0x2db/0x390 mm/slub.c:4591
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 __kmalloc_cache_noprof+0x143/0x320 mm/slub.c:4391
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 kernfs_fop_open+0x3f0/0xdd0 fs/kernfs/file.c:623
 do_dentry_open+0x9ae/0x1350 fs/open.c:965
 vfs_open+0x3b/0x350 fs/open.c:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x2ef1/0x3840 fs/namei.c:4046
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1461
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888034aeeb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888034aeeb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888034aeec00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888034aeec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888034aeed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/25 19:22 upstream b6add54ba618 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: slab-use-after-free Read in xfs_buf_rele
2025/08/18 07:23 upstream 8d561baae505 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in xfs_buf_rele
2025/08/05 07:12 upstream 35a813e010b9 f5bcc8dc .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in xfs_buf_rele
2025/08/20 22:23 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f5ae30d69d7 bd178e57 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Read in xfs_buf_rele
* Struck through repros no longer work on HEAD.