On Thu, Feb 20, 2025 at 08:00:24AM -0800, syzbot wrote: > ------------[ cut here ]------------ > kernel BUG at mm/filemap.c:1499! Tried to unlock a folio that wasn't locked. The entire log is interesting: https://syzkaller.appspot.com/x/log.txt?x=12af2fdf980000 It injects a failure which hits p9_tag_alloc() (so adding the 9p people to the cc) The page dump is: page: refcount:1 mapcount:0 mapping:ffff888035b30890 index:0x0 pfn:0x37e9a memcg:ffff88801c6be000 aops:v9fs_addr_operations ino:2721d72 dentry name(?):"file0" flags: 0xfff20000000020(lru|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff20000000020 ffffea0000e1d1c8 ffff88801b0b31a0 ffff888035b30890 raw: 0000000000000000 0000000000000000 00000001ffffffff ffff88801c6be000 page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio)) > Call Trace: > <TASK> > netfs_perform_write+0xc04/0x2140 fs/netfs/buffered_write.c:400 > netfs_buffered_write_iter_locked fs/netfs/buffered_write.c:445 [inline] > netfs_file_write_iter+0x494/0x550 fs/netfs/buffered_write.c:484 > v9fs_file_write_iter+0x9b/0x100 fs/9p/vfs_file.c:407 > new_sync_write fs/read_write.c:586 [inline] > vfs_write+0x5ae/0x1150 fs/read_write.c:679 > ksys_write+0x12b/0x250 fs/read_write.c:731
