* [syzbot] [bcachefs?] KASAN: slab-out-of-bounds Write in bch2_dirent_init_name
@ 2025-06-17 15:56 syzbot
2025-07-14 20:42 ` syzbot
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2025-06-17 15:56 UTC (permalink / raw)
To: kent.overstreet, linux-bcachefs, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 39dfc971e42d arm64/ptrace: Fix stack-out-of-bounds read in..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=14e965d4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=941e423b930a32dc
dashboard link: https://syzkaller.appspot.com/bug?extid=894877f2c4dd5fdea634
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
userspace arch: arm64
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ee1a7942f1b9/disk-39dfc971.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5b94ed3d0f7e/vmlinux-39dfc971.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9ce219d3314e/Image-39dfc971.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+894877f2c4dd5fdea634@syzkaller.appspotmail.com
bcachefs (loop3): bucket 0:11 gen 0 data type journal has wrong dirty_sectors: got 0, should be 256, fixing
Ratelimiting new instances of previous error
BUG: MAX_LOCKDEP_CHAINS too low!
turning off the locking correctness validator.
CPU: 1 UID: 0 PID: 9405 Comm: syz.3.515 Not tainted 6.16.0-rc1-syzkaller-g39dfc971e42d #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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
dump_stack+0x1c/0x28 lib/dump_stack.c:129
add_chain_cache kernel/locking/lockdep.c:-1 [inline]
lookup_chain_cache_add kernel/locking/lockdep.c:3858 [inline]
validate_chain kernel/locking/lockdep.c:3879 [inline]
__lock_acquire+0xf9c/0x30a4 kernel/locking/lockdep.c:5240
lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5871
percpu_down_write+0x6c/0x2f0 kernel/locking/percpu-rwsem.c:232
bch2_gc_accounting_done+0xe64/0x190c fs/bcachefs/disk_accounting.c:625
bch2_check_allocations+0x3a38/0x3c34 fs/bcachefs/btree_gc.c:1063
bch2_run_recovery_pass fs/bcachefs/recovery_passes.c:477 [inline]
__bch2_run_recovery_passes+0x29c/0xd18 fs/bcachefs/recovery_passes.c:532
bch2_run_recovery_passes+0x174/0x1f4 fs/bcachefs/recovery_passes.c:603
bch2_fs_recovery+0x1db8/0x2fd4 fs/bcachefs/recovery.c:974
bch2_fs_start+0x914/0xbc0 fs/bcachefs/super.c:1200
bch2_fs_get_tree+0x890/0xfd0 fs/bcachefs/fs.c:2489
vfs_get_tree+0x90/0x28c fs/super.c:1802
do_new_mount+0x228/0x814 fs/namespace.c:3885
path_mount+0x5b4/0xde0 fs/namespace.c:4209
do_mount fs/namespace.c:4222 [inline]
__do_sys_mount fs/namespace.c:4433 [inline]
__se_sys_mount fs/namespace.c:4410 [inline]
__arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4410
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
done
bcachefs (loop3): going read-write
bcachefs (loop3): journal_replay...
done
bcachefs (loop3): check_alloc_info... done
bcachefs (loop3): check_lrus... done
bcachefs (loop3): check_btree_backpointers... done
bcachefs (loop3): check_backpointers_to_extents... done
bcachefs (loop3): check_extents_to_backpointers...
bcachefs (loop3): scanning for missing backpointers in 4/128 buckets
done
bcachefs (loop3): check_alloc_to_lru_refs... done
bcachefs (loop3): bucket_gens_init... done
bcachefs (loop3): check_snapshot_trees... done
bcachefs (loop3): check_snapshots...
bcachefs (loop3): snapshot points to missing/incorrect tree:
u64s 8 type snapshot 0:4294967295:0 len 0 ver 0: subvol parent 0 children 0 0 subvol 1 tree 0, fixing
done
bcachefs (loop3): check_subvols... done
bcachefs (loop3): check_subvol_children... done
bcachefs (loop3): delete_dead_snapshots... done
bcachefs (loop3): check_inodes...
bcachefs (loop3): inode points to missing dirent
inum: 4099:4294967295
mode=100755
flags=(15300000)
journal_seq=5
hash_seed=fc917866faeb7b5b
hash_type=siphash
bi_size=1050
bi_sectors=8
bi_version=0
bi_atime=2770562249
bi_ctime=2770562249
bi_mtime=2770562249
bi_otime=2770562249
bi_uid=0
bi_gid=0
bi_nlink=0
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=0
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=4098
bi_dir_offset=8977922886548783724
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0, fixing
bcachefs (loop3): inode points to missing dirent
inum: 4100:4294967295
mode=120777
flags=(15300000)
journal_seq=4
hash_seed=f4891abdd5c0cd85
hash_type=siphash
bi_size=38
bi_sectors=8
bi_version=0
bi_atime=2770562249
bi_ctime=2780562352
bi_mtime=2770562249
bi_otime=2770562249
bi_uid=0
bi_gid=0
bi_nlink=0
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=0
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=4098
bi_dir_offset=5675548428000973578
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0, fixing
done
bcachefs (loop3): check_extents... done
bcachefs (loop3): check_indirect_extents... done
bcachefs (loop3): check_dirents...
bcachefs (loop3): dirent casefold does not match dir casefold
u64s 7 type dirent 4096:189491840996961599:U32_MAX len 0 ver 0: file0 -> 4098 type dir, fixing
==================================================================
BUG: KASAN: slab-out-of-bounds in bch2_dirent_init_name+0x28c/0x670 fs/bcachefs/dirent.c:271
Write of size 1985 at addr ffff0000ce7a8041 by task syz.3.515/9405
CPU: 0 UID: 0 PID: 9405 Comm: syz.3.515 Tainted: G W 6.16.0-rc1-syzkaller-g39dfc971e42d #0 PREEMPT
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189
__asan_memset+0x34/0x64 mm/kasan/shadow.c:84
bch2_dirent_init_name+0x28c/0x670 fs/bcachefs/dirent.c:271
bch2_dirent_create_key+0x1b4/0x434 fs/bcachefs/dirent.c:316
check_dirent fs/bcachefs/fsck.c:2223 [inline]
bch2_check_dirents+0x1d1c/0x27ac fs/bcachefs/fsck.c:2326
bch2_run_recovery_pass fs/bcachefs/recovery_passes.c:477 [inline]
__bch2_run_recovery_passes+0x29c/0xd18 fs/bcachefs/recovery_passes.c:532
bch2_run_recovery_passes+0x174/0x1f4 fs/bcachefs/recovery_passes.c:603
bch2_fs_recovery+0x1db8/0x2fd4 fs/bcachefs/recovery.c:974
bch2_fs_start+0x914/0xbc0 fs/bcachefs/super.c:1200
bch2_fs_get_tree+0x890/0xfd0 fs/bcachefs/fs.c:2489
vfs_get_tree+0x90/0x28c fs/super.c:1802
do_new_mount+0x228/0x814 fs/namespace.c:3885
path_mount+0x5b4/0xde0 fs/namespace.c:4209
do_mount fs/namespace.c:4222 [inline]
__do_sys_mount fs/namespace.c:4433 [inline]
__se_sys_mount fs/namespace.c:4410 [inline]
__arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4410
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Allocated by task 9405:
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]
__do_kmalloc_node mm/slub.c:4328 [inline]
__kmalloc_node_track_caller_noprof+0x304/0x4d0 mm/slub.c:4347
__do_krealloc mm/slub.c:4905 [inline]
krealloc_noprof+0x11c/0x2f0 mm/slub.c:4958
__bch2_trans_kmalloc+0x1f4/0xb8c fs/bcachefs/btree_iter.c:3187
bch2_trans_kmalloc_ip fs/bcachefs/btree_iter.h:604 [inline]
bch2_trans_kmalloc+0x10c/0x160 fs/bcachefs/btree_iter.h:616
bch2_dirent_create_key+0x50/0x434 fs/bcachefs/dirent.c:299
check_dirent fs/bcachefs/fsck.c:2223 [inline]
bch2_check_dirents+0x1d1c/0x27ac fs/bcachefs/fsck.c:2326
bch2_run_recovery_pass fs/bcachefs/recovery_passes.c:477 [inline]
__bch2_run_recovery_passes+0x29c/0xd18 fs/bcachefs/recovery_passes.c:532
bch2_run_recovery_passes+0x174/0x1f4 fs/bcachefs/recovery_passes.c:603
bch2_fs_recovery+0x1db8/0x2fd4 fs/bcachefs/recovery.c:974
bch2_fs_start+0x914/0xbc0 fs/bcachefs/super.c:1200
bch2_fs_get_tree+0x890/0xfd0 fs/bcachefs/fs.c:2489
vfs_get_tree+0x90/0x28c fs/super.c:1802
do_new_mount+0x228/0x814 fs/namespace.c:3885
path_mount+0x5b4/0xde0 fs/namespace.c:4209
do_mount fs/namespace.c:4222 [inline]
__do_sys_mount fs/namespace.c:4433 [inline]
__se_sys_mount fs/namespace.c:4410 [inline]
__arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4410
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
The buggy address belongs to the object at ffff0000ce7a8000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 65 bytes inside of
allocated 2048-byte region [ffff0000ce7a8000, ffff0000ce7a8800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e7a8
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 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 05ffc00000000040 ffff0000c0002000 dead000000000100 dead000000000122
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 05ffc00000000003 fffffdffc339ea01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff0000ce7a8700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff0000ce7a8780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000ce7a8800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff0000ce7a8880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000ce7a8900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
bcachefs (loop3): dirent casefold does not match dir casefold
u64s 7 type dirent 4096:1896155912177158345:U32_MAX len 0 ver 0: file3 -> 536870913 type reg, fixing
bcachefs (loop3): dirent casefold does not match dir casefold
u64s 7 type dirent 4096:2695648408715017799:U32_MAX len 0 ver 0: file2 -> 536870913 type reg, fixing
bcachefs (loop3): dirent casefold does not match dir casefold
u64s 7 type dirent 4096:4330382808765833931:U32_MAX len 0 ver 0: file1 -> 536870912 type reg, fixing
bcachefs (loop3): dirent casefold does not match dir casefold
u64s 8 type dirent 4096:8130059955150870709:U32_MAX len 0 ver 0: lost+found -> 4097 type dir, fixing
bcachefs (loop3): dirent casefold does not match dir casefold
u64s 8 type dirent 4096:9097378837824744618:U32_MAX len 0 ver 0: file.cold -> 536870914 type reg, fixing
bcachefs (loop3): directory 4096:4294967295 with wrong i_nlink: got 2, should be 0, fixing
done
bcachefs (loop3): check_xattrs... done
bcachefs (loop3): check_root... done
bcachefs (loop3): check_unreachable_inodes...
bcachefs (loop3): unreachable inode:
inum: 4099:4294967295
mode=100755
flags=(4300000)
journal_seq=22
hash_seed=fc917866faeb7b5b
hash_type=siphash
bi_size=1050
bi_sectors=8
bi_version=0
bi_atime=2770562249
bi_ctime=2770562249
bi_mtime=2770562249
bi_otime=2770562249
bi_uid=0
bi_gid=0
bi_nlink=0
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=0
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=0
bi_dir_offset=0
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0, fixing
bcachefs (loop3): creating //lost+found in subvol 1 snapshot 4294967295
bcachefs (loop3): creating //lost+found in subvol 1 snapshot 4294967295
bcachefs (loop3): creating //lost+found in subvol 1 snapshot 4294967295
bcachefs (loop3): unreachable inode:
inum: 4100:4294967295
mode=120777
flags=(4300000)
journal_seq=22
hash_seed=f4891abdd5c0cd85
hash_type=siphash
bi_size=38
bi_sectors=8
bi_version=0
bi_atime=2770562249
bi_ctime=2780562352
bi_mtime=2770562249
bi_otime=2770562249
bi_uid=0
bi_gid=0
bi_nlink=0
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=0
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=0
bi_dir_offset=0
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0, fixing
bcachefs (loop3): unreachable inode:
inum: 536870913:4294967295
mode=100755
flags=(15300000)
journal_seq=23
hash_seed=b68791a594a6d5ae
hash_type=siphash
bi_size=25769812776
bi_sectors=24
bi_version=0
bi_atime=2780562352
bi_ctime=2780562352
bi_mtime=2780562352
bi_otime=2780562352
bi_uid=0
bi_gid=0
bi_nlink=1
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=1
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=0
bi_dir_offset=2695648408715017799
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0, fixing
bcachefs (loop3): unreachable inode:
inum: 536870914:4294967295
mode=100755
flags=(15300000)
journal_seq=23
hash_seed=d483206f1ed95abf
hash_type=siphash
bi_size=100
bi_sectors=8
bi_version=1126999418470400
bi_atime=0
bi_ctime=0
bi_mtime=0
bi_otime=2780562352
bi_uid=2780562352
bi_gid=0
bi_nlink=2780562352
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=0
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=0
bi_dir_offset=9097378837824744618
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0, fixing
done
bcachefs (loop3): check_subvolume_structure... done
bcachefs (loop3): check_directory_structure...
bcachefs (loop3): inode points to dirent that does not point back:
u64s 10 type dirent 4096:8130059955150870709:U32_MAX len 0 ver 0: lost+found (casefold lost+found) -> 4101 type dir
inum: 4097:4294967295
mode=40700
flags=has_case_insensitive(15300400)
journal_seq=23
hash_seed=a9fcff247692d1ca
hash_type=siphash
bi_size=0
bi_sectors=0
bi_version=0
bi_atime=200535484
bi_ctime=200535484
bi_mtime=200535484
bi_otime=200535484
bi_uid=0
bi_gid=0
bi_nlink=0
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=0
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=4096
bi_dir_offset=8130059955150870709
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0
bcachefs (loop3): unreachable inode in check_directory_structure: ENOENT_dirent_doesnt_match_inode
u64s 17 type inode_v3 0:4097:U32_MAX len 0 ver 0:
mode=40700
flags=has_case_insensitive(15300400)
journal_seq=23
hash_seed=a9fcff247692d1ca
hash_type=siphash
bi_size=0
bi_sectors=0
bi_version=0
bi_atime=200535484
bi_ctime=200535484
bi_mtime=200535484
bi_otime=200535484
bi_uid=0
bi_gid=0
bi_nlink=0
bi_generation=0
bi_dev=0
bi_data_checksum=0
bi_compression=0
bi_project=0
bi_background_compression=0
bi_data_replicas=0
bi_promote_target=0
bi_foreground_target=0
bi_background_target=0
bi_erasure_code=0
bi_fields_set=0
bi_dir=4096
bi_dir_offset=8130059955150870709
bi_subvol=0
bi_parent_subvol=0
bi_nocow=0
bi_depth=0
bi_inodes_32bit=0
bi_casefold=0
bcachefs (loop3): check_path_loop(): error ENOENT_dirent_doesnt_match_inode
bcachefs (loop3): bch2_check_directory_structure(): error ENOENT_dirent_doesnt_match_inode
bcachefs (loop3): error in recovery: ENOENT_dirent_doesnt_match_inodeemergency read only at seq 25
bcachefs (loop3): bch2_fs_start(): error starting filesystem ENOENT_dirent_doesnt_match_inode
bcachefs (loop3): shutting down
bcachefs (loop3): shutdown complete
bcachefs: bch2_fs_get_tree() error: ENOENT_dirent_doesnt_match_inode
---
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* Re: [syzbot] [bcachefs?] KASAN: slab-out-of-bounds Write in bch2_dirent_init_name
2025-06-17 15:56 [syzbot] [bcachefs?] KASAN: slab-out-of-bounds Write in bch2_dirent_init_name syzbot
@ 2025-07-14 20:42 ` syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2025-07-14 20:42 UTC (permalink / raw)
To: kent.overstreet, linux-bcachefs, linux-kernel, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: 347e9f5043c8 Linux 6.16-rc6
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13c670f0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f09d04131ef56b22
dashboard link: https://syzkaller.appspot.com/bug?extid=894877f2c4dd5fdea634
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133cc7d4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11a4518c580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7d8e110455be/disk-347e9f50.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4dee9ae820cb/vmlinux-347e9f50.xz
kernel image: https://storage.googleapis.com/syzbot-assets/26ea07888a9b/bzImage-347e9f50.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/df51adb1876e/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+894877f2c4dd5fdea634@syzkaller.appspotmail.com
bcachefs (loop0): done starting filesystem
==================================================================
BUG: KASAN: slab-out-of-bounds in bch2_dirent_init_name+0x396/0x8b0 fs/bcachefs/dirent.c:273
Write of size 1985 at addr ffff8881496a3041 by task syz-executor478/5839
CPU: 0 UID: 0 PID: 5839 Comm: syz-executor478 Not tainted 6.16.0-rc6-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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/0x230 mm/kasan/report.c:480
kasan_report+0x118/0x150 mm/kasan/report.c:593
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
__asan_memset+0x22/0x50 mm/kasan/shadow.c:84
bch2_dirent_init_name+0x396/0x8b0 fs/bcachefs/dirent.c:273
bch2_dirent_create_key+0x2a1/0x5f0 fs/bcachefs/dirent.c:315
bch2_dirent_create+0xc5/0xc80 fs/bcachefs/dirent.c:358
bch2_link_trans+0x39e/0x560 fs/bcachefs/namei.c:241
__bch2_link+0x231/0x3f0 fs/bcachefs/fs.c:776
bch2_link+0x197/0x220 fs/bcachefs/fs.c:805
vfs_link+0x4ea/0x6e0 fs/namei.c:4863
do_linkat+0x272/0x560 fs/namei.c:4933
__do_sys_link fs/namei.c:4967 [inline]
__se_sys_link fs/namei.c:4965 [inline]
__x64_sys_link+0x82/0x90 fs/namei.c:4965
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: 0033:0x7f5e63959b19
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffee09b8bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 0031656c69662f2e RCX: 00007f5e63959b19
RDX: 00007f5e63959b19 RSI: 0000200000000240 RDI: 00002000000001c0
RBP: 00007f5e639d25f0 R08: 00005555839934c0 R09: 00005555839934c0
R10: 0000000000005a9b R11: 0000000000000246 R12: 00007ffee09b8c00
R13: 00007ffee09b8e28 R14: 431bde82d7b634db R15: 00007f5e639a203b
</TASK>
Allocated by task 5839:
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:377 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4328 [inline]
__kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4340
kmalloc_noprof include/linux/slab.h:909 [inline]
__bch2_trans_kmalloc+0x396/0x9d0 fs/bcachefs/btree_iter.c:3242
bch2_trans_kmalloc_ip fs/bcachefs/btree_iter.h:604 [inline]
bch2_trans_kmalloc fs/bcachefs/btree_iter.h:616 [inline]
bch2_dirent_create_key+0x113/0x5f0 fs/bcachefs/dirent.c:298
bch2_dirent_create+0xc5/0xc80 fs/bcachefs/dirent.c:358
bch2_link_trans+0x39e/0x560 fs/bcachefs/namei.c:241
__bch2_link+0x231/0x3f0 fs/bcachefs/fs.c:776
bch2_link+0x197/0x220 fs/bcachefs/fs.c:805
vfs_link+0x4ea/0x6e0 fs/namei.c:4863
do_linkat+0x272/0x560 fs/namei.c:4933
__do_sys_link fs/namei.c:4967 [inline]
__se_sys_link fs/namei.c:4965 [inline]
__x64_sys_link+0x82/0x90 fs/namei.c:4965
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 ffff8881496a3000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 65 bytes inside of
allocated 2048-byte region [ffff8881496a3000, ffff8881496a3800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1496a0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801a442000 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801a442000 0000000000000000 dead000000000001
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 057ff00000000003 ffffea000525a801 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 13597243606, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
prep_new_page mm/page_alloc.c:1712 [inline]
get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
alloc_slab_page mm/slub.c:2451 [inline]
allocate_slab+0x8a/0x3b0 mm/slub.c:2619
new_slab mm/slub.c:2673 [inline]
___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
__slab_alloc mm/slub.c:3949 [inline]
__slab_alloc_node mm/slub.c:4024 [inline]
slab_alloc_node mm/slub.c:4185 [inline]
__kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4354
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
__media_device_register+0x58/0x280 drivers/media/mc/mc-device.c:720
vivid_create_devnodes+0x2037/0x2bf0 drivers/media/test-drivers/vivid/vivid-core.c:1749
vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:2042 [inline]
vivid_probe+0x5035/0x7180 drivers/media/test-drivers/vivid/vivid-core.c:2095
platform_probe+0x148/0x1d0 drivers/base/platform.c:1404
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x26a/0x9a0 drivers/base/dd.c:657
__driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:799
driver_probe_device+0x4f/0x430 drivers/base/dd.c:829
__driver_attach+0x452/0x700 drivers/base/dd.c:1215
bus_for_each_dev+0x230/0x2b0 drivers/base/bus.c:370
page_owner free stack trace missing
Memory state around the buggy address:
ffff8881496a3700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881496a3780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881496a3800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881496a3880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881496a3900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
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2025-06-17 15:56 [syzbot] [bcachefs?] KASAN: slab-out-of-bounds Write in bch2_dirent_init_name syzbot
2025-07-14 20:42 ` syzbot
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