[syzbot] [bcachefs?] KASAN: slab-out-of-bounds Read in bch2_sb_clean_to_text

From: syzbot
Date: Sun May 05 2024 - 14:26:13 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 7367539ad4b0 Merge tag 'cxl-fixes-6.9-rc7' of git://git.ke..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11711898980000
kernel config: https://syzkaller.appspot.com/x/.config?x=d2f00edef461175
dashboard link: https://syzkaller.appspot.com/bug?extid=c48865e11e7e893ec4ab
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1043897f180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145c078b180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/03bd77f8af70/disk-7367539a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eb03a61f9582/vmlinux-7367539a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e4c5c654b571/bzImage-7367539a.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2d31172220b2/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c48865e11e7e893ec4ab@xxxxxxxxxxxxxxxxxxxxxxxxx

loop0: detected capacity change from 0 to 32768
==================================================================
BUG: KASAN: slab-out-of-bounds in bch2_sb_clean_to_text+0x17f/0x230 fs/bcachefs/sb-clean.c:298
Read of size 1 at addr ffff888023ef6004 by task syz-executor493/5073

CPU: 0 PID: 5073 Comm: syz-executor493 Not tainted 6.9.0-rc6-syzkaller-00234-g7367539ad4b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
bch2_sb_clean_to_text+0x17f/0x230 fs/bcachefs/sb-clean.c:298
bch2_sb_field_validate+0x1f7/0x2d0 fs/bcachefs/super-io.c:1211
bch2_sb_validate+0xa79/0xe10 fs/bcachefs/super-io.c:468
__bch2_read_super+0xc9a/0x1460 fs/bcachefs/super-io.c:822
bch2_fs_open+0x246/0xdf0 fs/bcachefs/super.c:2049
bch2_mount+0x71d/0x1320 fs/bcachefs/fs.c:1903
legacy_get_tree+0xee/0x190 fs/fs_context.c:662
vfs_get_tree+0x90/0x2a0 fs/super.c:1779
do_new_mount+0x2be/0xb40 fs/namespace.c:3352
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a126618fa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffe44de6bb8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe44de6bd0 RCX: 00007f2a126618fa
RDX: 0000000020011a00 RSI: 0000000020011a40 RDI: 00007ffe44de6bd0
RBP: 0000000000000004 R08: 00007ffe44de6c10 R09: 00000000000119fe
R10: 0000000003004000 R11: 0000000000000282 R12: 0000000003004000
R13: 00007ffe44de6c10 R14: 0000000000000003 R15: 0000000001000000
</TASK>

Allocated by task 5073:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slub.c:3966 [inline]
__kmalloc_node_track_caller+0x24e/0x4e0 mm/slub.c:3986
__do_krealloc mm/slab_common.c:1192 [inline]
krealloc+0x7d/0x120 mm/slab_common.c:1225
bch2_sb_realloc+0x2fc/0x660 fs/bcachefs/super-io.c:189
read_one_super+0x7d7/0x3a10 fs/bcachefs/super-io.c:659
__bch2_read_super+0x65a/0x1460 fs/bcachefs/super-io.c:750
bch2_fs_open+0x246/0xdf0 fs/bcachefs/super.c:2049
bch2_mount+0x71d/0x1320 fs/bcachefs/fs.c:1903
legacy_get_tree+0xee/0x190 fs/fs_context.c:662
vfs_get_tree+0x90/0x2a0 fs/super.c:1779
do_new_mount+0x2be/0xb40 fs/namespace.c:3352
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888023ef4000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 4 bytes to the right of
allocated 8192-byte region [ffff888023ef4000, ffff888023ef6000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x23ef0
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888015042280 ffffea0000910a00 0000000000000005
raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
head: 00fff00000000840 ffff888015042280 ffffea0000910a00 0000000000000005
head: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
head: 00fff00000000003 ffffea00008fbc01 ffffea00008fbc48 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4736, tgid 1480517225 (sh), ts 4736, free_ts 31493460772
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
prep_new_page mm/page_alloc.c:1541 [inline]
get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
__alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2175
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2391
___slab_alloc+0xc73/0x1260 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
kmalloc_trace+0x269/0x360 mm/slub.c:3992
kmalloc include/linux/slab.h:628 [inline]
kzalloc include/linux/slab.h:749 [inline]
tomoyo_print_bprm security/tomoyo/audit.c:26 [inline]
tomoyo_init_log+0x11ce/0x2050 security/tomoyo/audit.c:264
tomoyo_supervisor+0x38a/0x11f0 security/tomoyo/common.c:2089
tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
tomoyo_env_perm+0x178/0x210 security/tomoyo/environ.c:63
tomoyo_environ security/tomoyo/domain.c:672 [inline]
tomoyo_find_next_domain+0x1384/0x1cf0 security/tomoyo/domain.c:878
tomoyo_bprm_check_security+0x115/0x180 security/tomoyo/tomoyo.c:102
security_bprm_check+0x65/0x90 security/security.c:1191
search_binary_handler fs/exec.c:1766 [inline]
exec_binprm fs/exec.c:1820 [inline]
bprm_execve+0xa56/0x17c0 fs/exec.c:1872
do_execveat_common+0x553/0x700 fs/exec.c:1979
do_execve fs/exec.c:2053 [inline]
__do_sys_execve fs/exec.c:2129 [inline]
__se_sys_execve fs/exec.c:2124 [inline]
__x64_sys_execve+0x92/0xb0 fs/exec.c:2124
page last free pid 4734 tgid 4734 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1141 [inline]
free_unref_page_prepare+0x97b/0xaa0 mm/page_alloc.c:2347
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
discard_slab mm/slub.c:2437 [inline]
__put_partials+0xeb/0x130 mm/slub.c:2906
put_cpu_partial+0x17c/0x250 mm/slub.c:2981
__slab_free+0x2ea/0x3d0 mm/slub.c:4151
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3798 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc+0x174/0x340 mm/slub.c:3852
getname_flags+0xbd/0x4f0 fs/namei.c:139
do_sys_openat2+0xd2/0x1d0 fs/open.c:1400
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1432
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff888023ef5f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888023ef5f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888023ef6000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888023ef6080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888023ef6100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

---
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