[v6.6] BUG: Bad page state in z_erofs_do_read_page

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=122dbd0c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=b6353e35ae2bab997538
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6353e...@syzkaller.appspotmail.com

BUG: Bad page state in process syz-executor pfn:65041
page:ffffea0001941040 refcount:0 mapcount:0 mapping:ffff888075c4f800 index:0x2 pfn:0x65041
aops:z_erofs_cache_aops ino:0
flags: 0xfff00000000001(locked|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000001 dead000000000100 dead000000000122 ffff888075c4f800
raw: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x192840(GFP_NOWAIT|__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 18527, tgid 18526 (syz.7.3455), ts 1259134139070, free_ts 1258930978052
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
prep_new_page mm/page_alloc.c:1561 [inline]
get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
__alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
z_erofs_bind_cache fs/erofs/zdata.c:599 [inline]
z_erofs_pcluster_begin fs/erofs/zdata.c:883 [inline]
z_erofs_do_read_page+0x20c0/0x3680 fs/erofs/zdata.c:1018
z_erofs_pcluster_readmore+0x2cf/0x450 fs/erofs/zdata.c:1818
z_erofs_read_folio+0x208/0x540 fs/erofs/zdata.c:1838
filemap_read_folio+0x167/0x760 mm/filemap.c:2420
do_read_cache_folio+0x470/0x7e0 mm/filemap.c:3789
erofs_bread+0x16f/0x630 fs/erofs/data.c:48
erofs_find_target_block fs/erofs/namei.c:103 [inline]
erofs_namei+0x28c/0xf00 fs/erofs/namei.c:177
erofs_lookup+0x135/0x310 fs/erofs/namei.c:206
lookup_open fs/namei.c:3466 [inline]
open_last_lookups fs/namei.c:3556 [inline]
path_openat+0x10b8/0x3190 fs/namei.c:3786
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
do_sys_open fs/open.c:1434 [inline]
__do_sys_openat fs/open.c:1450 [inline]
__se_sys_openat fs/open.c:1445 [inline]
__x64_sys_openat+0x139/0x160 fs/open.c:1445
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1154 [inline]
free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
release_pages+0x1fa0/0x2220 mm/swap.c:1022
tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
exit_mmap+0x3f0/0xb50 mm/mmap.c:3305
__mmput+0x118/0x3c0 kernel/fork.c:1355
exit_mm+0x1da/0x2c0 kernel/exit.c:569
do_exit+0x886/0x23c0 kernel/exit.c:861
do_group_exit+0x21b/0x2d0 kernel/exit.c:1023
get_signal+0x12fc/0x1400 kernel/signal.c:2902
arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
Modules linked in:
CPU: 1 PID: 18183 Comm: syz-executor Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
bad_page+0x14b/0x170 mm/page_alloc.c:512
free_page_is_bad mm/page_alloc.c:961 [inline]
free_pages_prepare mm/page_alloc.c:1146 [inline]
free_unref_page_prepare+0x887/0x8e0 mm/page_alloc.c:2336
free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
detach_page_private include/linux/pagemap.h:539 [inline]
erofs_try_to_free_all_cached_pages+0x295/0x600 fs/erofs/zdata.c:651
erofs_try_to_release_workgroup fs/erofs/utils.c:132 [inline]
erofs_shrink_workstation+0x118/0x290 fs/erofs/utils.c:161
erofs_shrinker_unregister+0x5d/0x170 fs/erofs/utils.c:198
erofs_put_super+0x4e/0x150 fs/erofs/super.c:812
generic_shutdown_super+0x134/0x2b0 fs/super.c:693
kill_block_super+0x44/0x90 fs/super.c:1660
erofs_kill_sb+0x4c/0x140 fs/erofs/super.c:794
deactivate_locked_super+0x97/0x100 fs/super.c:481
cleanup_mnt+0x429/0x4c0 fs/namespace.c:1250
task_work_run+0x1ce/0x250 kernel/task_work.c:239
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa510f8fc57
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffca24b9798 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fa511010925 RCX: 00007fa510f8fc57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffca24b9850
RBP: 00007ffca24b9850 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffca24ba8e0
R13: 00007fa511010925 R14: 0000000000133776 R15: 00007ffca24ba920
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y

console output: https://syzkaller.appspot.com/x/log.txt?x=128d1b0c580000

kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=b6353e35ae2bab997538
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=168d1b0c580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1376cdd4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/4b17bcfaacea/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=17120b0c580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6353e...@syzkaller.appspotmail.com

BUG: Bad page state in process syz-executor154 pfn:2fb15
page:ffffea0000bec540 refcount:0 mapcount:0 mapping:ffff8880789787c8 index:0x2 pfn:0x2fb15

aops:z_erofs_cache_aops ino:0
flags: 0xfff00000000001(locked|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()

raw: 00fff00000000001 dead000000000100 dead000000000122 ffff8880789787c8

raw: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
page_owner tracks the page as allocated

page last allocated via order 0, migratetype Unmovable, gfp_mask 0x92840(GFP_NOWAIT|__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_NOMEMALLOC), pid 5770, tgid 5770 (syz-executor154), ts 79594811923, free_ts 79578801476

free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
discard_slab mm/slub.c:2122 [inline]
__unfreeze_partials+0x1cf/0x210 mm/slub.c:2662
put_cpu_partial+0x17c/0x250 mm/slub.c:2738
__slab_free+0x31d/0x410 mm/slub.c:3686
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
slab_alloc_node mm/slub.c:3485 [inline]
slab_alloc mm/slub.c:3493 [inline]
__kmem_cache_alloc_lru mm/slub.c:3500 [inline]
kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509
getname_flags+0xbb/0x500 fs/namei.c:140
do_sys_openat2+0xcb/0x1c0 fs/open.c:1413

do_sys_open fs/open.c:1434 [inline]
__do_sys_openat fs/open.c:1450 [inline]
__se_sys_openat fs/open.c:1445 [inline]
__x64_sys_openat+0x139/0x160 fs/open.c:1445
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81

entry_SYSCALL_64_after_hwframe+0x68/0xd2
Modules linked in:
CPU: 0 PID: 5769 Comm: syz-executor154 Not tainted 6.6.94-syzkaller #0

RIP: 0033:0x7fdca0404407
Code: 07 00 48 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffdc3073a48 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 000000000001368f RCX: 00007fdca0404407
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffdc3073b00
RBP: 00007ffdc3073b00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000206 R12: 00007ffdc3074b60
R13: 00005555636206c0 R14: 0000000000000001 R15: 431bde82d7b634db
</TASK>


---
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