On Thu, May 9, 2024 at 1:49 PM Hillf Danton <hdanton@xxxxxxxx> wrote: > > On Thu, 9 May 2024 09:37:24 +0300 Amir Goldstein <amir73il@xxxxxxxxx> > > On Thu, May 9, 2024 at 2:19 AM Hillf Danton <hdanton@xxxxxxxx> wrote: > > > On Tue, 07 May 2024 22:36:18 -0700 > > > > syzbot has found a reproducer for the following issue on: > > > > > > > > HEAD commit: dccb07f2914c Merge tag 'for-6.9-rc7-tag' of git://git.kern.. > > > > git tree: upstream > > > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=137daa6c980000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=9d7ea7de0cb32587 > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=4c493dcd5a68168a94b2 > > > > 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=1134f3c0980000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1367a504980000 > > > > > > > > Downloadable assets: > > > > disk image: https://storage.googleapis.com/syzbot-assets/ea1961ce01fe/disk-dccb07f2.raw.xz > > > > vmlinux: https://storage.googleapis.com/syzbot-assets/445a00347402/vmlinux-dccb07f2.xz > > > > kernel image: https://storage.googleapis.com/syzbot-assets/461aed7c4df3/bzImage-dccb07f2.xz > > > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > > Reported-by: syzbot+4c493dcd5a68168a94b2@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > > > > > ====================================================== > > > > WARNING: possible circular locking dependency detected > > > > 6.9.0-rc7-syzkaller-00012-gdccb07f2914c #0 Not tainted > > > > ------------------------------------------------------ > > > > syz-executor149/5078 is trying to acquire lock: > > > > ffff88802a978888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x53/0x3b0 fs/kernfs/file.c:154 > > > > > > > > but task is already holding lock: > > > > ffff88802d80b540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb7/0xd60 fs/seq_file.c:182 > > > > > > > > which lock already depends on the new lock. > > > > > > > > > > > > the existing dependency chain (in reverse order) is: > > > > > > > > -> #4 (&p->lock){+.+.}-{3:3}: > > > > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 > > > > __mutex_lock_common kernel/locking/mutex.c:608 [inline] > > > > __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 > > > > seq_read_iter+0xb7/0xd60 fs/seq_file.c:182 > > > > call_read_iter include/linux/fs.h:2104 [inline] > > > > copy_splice_read+0x662/0xb60 fs/splice.c:365 > > > > do_splice_read fs/splice.c:985 [inline] > > > > splice_file_to_pipe+0x299/0x500 fs/splice.c:1295 > > > > do_sendfile+0x515/0xdc0 fs/read_write.c:1301 > > > > __do_sys_sendfile64 fs/read_write.c:1362 [inline] > > > > __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1348 > > > > 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 > > > > > > > > -> #3 (&pipe->mutex){+.+.}-{3:3}: > > > > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 > > > > __mutex_lock_common kernel/locking/mutex.c:608 [inline] > > > > __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 > > > > iter_file_splice_write+0x335/0x14e0 fs/splice.c:687 > > > > backing_file_splice_write+0x2bc/0x4c0 fs/backing-file.c:289 > > > > ovl_splice_write+0x3cf/0x500 fs/overlayfs/file.c:379 > > > > do_splice_from fs/splice.c:941 [inline] > > > > do_splice+0xd77/0x1880 fs/splice.c:1354 > > file_start_write(out); > ret = do_splice_from(ipipe, out, &offset, len, flags); > file_end_write(out); > > The correct locking order is > > sb_writers This is sb of overlayfs > inode lock This is real inode See comment above ovl_lockdep_annotate_inode_mutex_key() for more details. Thanks, Amir.
