[v5.15] BUG: sleeping function called from invalid context in z_erofs_do_read_page

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1386f522580000
kernel config: https://syzkaller.appspot.com/x/.config?x=30e28339904629ca
dashboard link: https://syzkaller.appspot.com/bug?extid=b679814316073f532e4a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a778cfe5926b/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d2cfafb4eb48/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/845a4677be47/bzImage-68efe5a6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b67981...@syzkaller.appspotmail.com

erofs: (device loop0): z_erofs_readahead: readahead error at page 49 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 48 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 47 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 46 @ nid 36
BUG: sleeping function called from invalid context at include/linux/sched/mm.h:209
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4894, name: syz.0.122
1 lock held by syz.0.122/4894:
#0: ffff888072fc4320 (mapping.invalidate_lock#4){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
#0: ffff888072fc4320 (mapping.invalidate_lock#4){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x198/0x940 mm/readahead.c:195
Preemption disabled at:
[<ffffffff8398fa12>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fa12>] z_erofs_reload_indexes+0x1c2/0x590 fs/erofs/zmap.c:130
CPU: 1 PID: 4894 Comm: syz.0.122 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
___might_sleep+0x493/0x610 kernel/sched/core.c:9658
might_alloc include/linux/sched/mm.h:209 [inline]
slab_pre_alloc_hook+0x42/0xc0 mm/slab.h:492
slab_alloc_node mm/slub.c:3139 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc+0x3d/0x290 mm/slub.c:3238
kmem_cache_zalloc include/linux/slab.h:728 [inline]
z_erofs_alloc_pcluster fs/erofs/zdata.c:74 [inline]
z_erofs_register_collection fs/erofs/zdata.c:480 [inline]
z_erofs_collector_begin fs/erofs/zdata.c:557 [inline]
z_erofs_do_read_page+0x6c1/0x26c0 fs/erofs/zdata.c:693
z_erofs_readahead+0x85d/0x1140 fs/erofs/zdata.c:1449
read_pages+0x175/0x930 mm/readahead.c:130
page_cache_ra_unbounded+0x838/0x940 mm/readahead.c:239
do_page_cache_ra mm/readahead.c:269 [inline]
force_page_cache_ra+0x3e5/0x440 mm/readahead.c:301
force_page_cache_readahead mm/internal.h:78 [inline]
generic_fadvise+0x530/0x7f0 mm/fadvise.c:107
vfs_fadvise mm/fadvise.c:186 [inline]
ksys_fadvise64_64 mm/fadvise.c:200 [inline]
__do_sys_fadvise64 mm/fadvise.c:215 [inline]
__se_sys_fadvise64 mm/fadvise.c:213 [inline]
__x64_sys_fadvise64+0x139/0x180 mm/fadvise.c:213
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff3d3bbccb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff3d1e18028 EFLAGS: 00000246 ORIG_RAX: 00000000000000dd
RAX: ffffffffffffffda RBX: 00007ff3d3e37fa0 RCX: 00007ff3d3bbccb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007ff3d3c2abf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff3d3e38038 R14: 00007ff3d3e37fa0 R15: 00007ffcbc4d7528
</TASK>
erofs: (device loop0): z_erofs_readahead: readahead error at page 44 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: invalid lookback distance 0 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 43 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 41 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 38 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 37 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 35 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 34 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 33 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 32 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 31 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 29 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 28 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 27 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 26 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 25 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 24 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 23 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 22 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 21 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 20 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 19 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 18 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 17 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 16 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 15 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 14 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 13 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 12 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 9 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 8 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 7 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 6 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 5 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 4 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 3 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: invalid lookback distance 0 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 1 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: invalid lookback distance 0 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 0 @ nid 36
attempt to access beyond end of device
loop0: rw=524288, want=720, limit=16
attempt to access beyond end of device
loop0: rw=524288, want=525144, limit=16
attempt to access beyond end of device
loop0: rw=524288, want=72, limit=16
attempt to access beyond end of device
loop0: rw=524288, want=1183600, limit=16
attempt to access beyond end of device
loop0: rw=524288, want=296, limit=16
attempt to access beyond end of device
loop0: rw=524288, want=1048976, limit=16
attempt to access beyond end of device
loop0: rw=524288, want=3670472, limit=16
attempt to access beyond end of device
loop0: rw=524288, want=790384, limit=16
BUG: scheduling while atomic: syz.0.122/4894/0x00000005
no locks held by syz.0.122/4894.
Modules linked in:
Preemption disabled at:
[<ffffffff8398fa12>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fa12>] z_erofs_reload_indexes+0x1c2/0x590 fs/erofs/zmap.c:130


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1132db9a580000

kernel config: https://syzkaller.appspot.com/x/.config?x=30e28339904629ca
dashboard link: https://syzkaller.appspot.com/bug?extid=b679814316073f532e4a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162e6b9a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1316f522580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a778cfe5926b/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d2cfafb4eb48/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/845a4677be47/bzImage-68efe5a6.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/847268fd7ec1/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=176aa852580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b67981...@syzkaller.appspotmail.com

erofs: (device loop0): z_erofs_readahead: readahead error at page 50 @ nid 36

erofs: (device loop0): z_erofs_readahead: readahead error at page 49 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 48 @ nid 36
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 47 @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 46 @ nid 36
BUG: sleeping function called from invalid context at include/linux/sched/mm.h:209

in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4338, name: syz.0.17
1 lock held by syz.0.17/4338:
#0: ffff88805b5f8320 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
#0: ffff88805b5f8320 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x198/0x940 mm/readahead.c:195

Preemption disabled at:
[<ffffffff8398fa12>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fa12>] z_erofs_reload_indexes+0x1c2/0x590 fs/erofs/zmap.c:130

CPU: 0 PID: 4338 Comm: syz.0.17 Not tainted syzkaller #0

RIP: 0033:0x7ff830acbcb9

Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007ffc583cbff8 EFLAGS: 00000246 ORIG_RAX: 00000000000000dd
RAX: ffffffffffffffda RBX: 00007ff830d46fa0 RCX: 00007ff830acbcb9

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004

RBP: 00007ff830b39bf7 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000

R13: 00007ff830d46fac R14: 00007ff830d46fa0 R15: 00007ff830d46fa0

BUG: scheduling while atomic: syz.0.17/4338/0x00000005
no locks held by syz.0.17/4338.

Modules linked in:
Preemption disabled at:
[<ffffffff8398fa12>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fa12>] z_erofs_reload_indexes+0x1c2/0x590 fs/erofs/zmap.c:130


---

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