[syzbot] [btrfs?] kernel BUG in wait_subpage_spinlock

[syzbot <syzbot+d6f123d4060990f0f3ff@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    5dd1818b15d9 Merge tag 'for-next-keys-v7.3-rc4' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1694d7f9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c3bddd52b22c2498
dashboard link: https://syzkaller.appspot.com/bug?extid=d6f123d4060990f0f3ff
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-5dd1818b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fa126b13cb66/vmlinux-5dd1818b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e10c187acaf6/bzImage-5dd1818b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d6f123d4060990f0f3ff@syzkaller.appspotmail.com

BTRFS info (device loop0): space_info DATA+METADATA (sub-group id 0) has 24576 free, is not full
BTRFS info (device loop0): space_info total=3276800, used=49152, pinned=16384, reserved=0, may_use=3186688, readonly=0 zone_unusable=0
BTRFS info (device loop0): global_block_rsv: size 1048576 reserved 1048576
BTRFS info (device loop0): trans_block_rsv: size 0 reserved 0
BTRFS info (device loop0): chunk_block_rsv: size 0 reserved 0
BTRFS info (device loop0): remap_block_rsv: size 0 reserved 0
BTRFS info (device loop0): delayed_block_rsv: size 0 reserved 0
BTRFS info (device loop0): delayed_refs_rsv: size 32768 reserved 32768
assertion failed: folio_test_private(folio) && folio_get_private(folio), in fs/btrfs/inode.c:7616
------------[ cut here ]------------
kernel BUG at fs/btrfs/inode.c:7616!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5325 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:wait_subpage_spinlock+0x380/0x390 fs/btrfs/inode.c:7616
Code: 17 aa fd eb 05 e8 40 17 aa fd 48 c7 c7 00 d2 59 8c 48 c7 c6 c0 06 5a 8c 48 c7 c2 e0 d2 59 8c b9 c0 1d 00 00 e8 a1 f3 09 fd 90 <0f> 0b 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90
RSP: 0018:ffffc9000f15e048 EFLAGS: 00010246
RAX: 0000000000000061 RBX: ffffea0001508f00 RCX: 5c8637085c6b4a00
RDX: 0000000000000000 RSI: 8000000000000000 RDI: 0000000000000000
RBP: 1ffffd40002a11e0 R08: ffffc9000f15ddc7 R09: 1ffff92001e2bbb8
R10: dffffc0000000000 R11: fffff52001e2bbb9 R12: 0000000000000002
R13: 0000000000004000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007fd4260436c0(0000) GS:ffff88808c2c3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd426062f68 CR3: 000000004387c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 btrfs_invalidate_folio+0x26e/0xc50 fs/btrfs/inode.c:7698
 extent_writepage fs/btrfs/extent_io.c:2058 [inline]
 extent_write_cache_pages fs/btrfs/extent_io.c:2843 [inline]
 btrfs_writepages+0x129f/0x28c0 fs/btrfs/extent_io.c:2975
 do_writepages+0x338/0x560 mm/page-writeback.c:2560
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range+0x1ef/0x2f0 mm/filemap.c:412
 btrfs_start_ordered_extent_nowriteback+0x305/0x6e0 fs/btrfs/ordered-data.c:-1
 btrfs_start_ordered_extent fs/btrfs/ordered-data.h:203 [inline]
 btrfs_page_mkwrite+0x856/0x1a40 fs/btrfs/file.c:1909
 do_page_mkwrite+0x147/0x310 mm/memory.c:3816
 wp_page_shared mm/memory.c:4217 [inline]
 do_wp_page+0x1a9c/0x4b80 mm/memory.c:4440
 handle_pte_fault mm/memory.c:6582 [inline]
 __handle_mm_fault mm/memory.c:6707 [inline]
 handle_mm_fault+0x15d7/0x3750 mm/memory.c:6876
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x1675/0x2750 mm/gup.c:1428
 __get_user_pages_locked mm/gup.c:1752 [inline]
 __gup_longterm_locked+0x1032/0x15c0 mm/gup.c:2471
 gup_fast_fallback+0x1d92/0x20e0 mm/gup.c:3209
 iov_iter_extract_user_pages lib/iov_iter.c:1776 [inline]
 iov_iter_extract_pages+0x3a1/0x690 lib/iov_iter.c:1845
 iov_iter_extract_bvecs+0x272/0xb40 lib/iov_iter.c:1957
 bio_iov_iter_get_pages+0x5ae/0xee0 block/bio.c:1309
 blkdev_iov_iter_get_pages block/fops.c:49 [inline]
 __blkdev_direct_IO+0x661/0xf60 block/fops.c:219
 blkdev_direct_IO+0x121d/0x17b0 block/fops.c:435
 blkdev_read_iter+0x223/0x420 block/fops.c:816
 aio_read+0x33a/0x4d0 fs/aio.c:1656
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0x774/0x13d0 fs/aio.c:2106
 __do_sys_io_submit fs/aio.c:2165 [inline]
 __se_sys_io_submit+0x195/0x340 fs/aio.c:2135
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd42519e159
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:00007fd426042fe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007fd425426090 RCX: 00007fd42519e159
RDX: 00002000000000c0 RSI: 00000000000000ca RDI: 00007fd426022000
RBP: 00007fd42523506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd425426128 R14: 00007fd425426090 R15: 00007ffec6e38c28
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:wait_subpage_spinlock+0x380/0x390 fs/btrfs/inode.c:7616
Code: 17 aa fd eb 05 e8 40 17 aa fd 48 c7 c7 00 d2 59 8c 48 c7 c6 c0 06 5a 8c 48 c7 c2 e0 d2 59 8c b9 c0 1d 00 00 e8 a1 f3 09 fd 90 <0f> 0b 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90
RSP: 0018:ffffc9000f15e048 EFLAGS: 00010246
RAX: 0000000000000061 RBX: ffffea0001508f00 RCX: 5c8637085c6b4a00
RDX: 0000000000000000 RSI: 8000000000000000 RDI: 0000000000000000
RBP: 1ffffd40002a11e0 R08: ffffc9000f15ddc7 R09: 1ffff92001e2bbb8
R10: dffffc0000000000 R11: fffff52001e2bbb9 R12: 0000000000000002
R13: 0000000000004000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007fd4260436c0(0000) GS:ffff88808c2c3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2823e512c0 CR3: 000000004387c000 CR4: 0000000000352ef0


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