On Sun, Nov 5, 2017 at 1:25 PM, syzbot <bot+f99f3a0db9007f4f4e32db54229a240c4fe57c15@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzkaller hit the following crash on > 7a95bdb092c66b6473aa2fc848862ae557ab08f7 > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > ====================================================== > WARNING: possible circular locking dependency detected > 4.13.0+ #84 Not tainted > ------------------------------------------------------ > loop0/2986 is trying to acquire lock: > (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff8186f9ec>] inode_lock > include/linux/fs.h:712 [inline] > (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff8186f9ec>] > generic_file_write_iter+0xdc/0x7a0 mm/filemap.c:3151 > > but now in release context of a crosslock acquired at the following: > ((complete)&ret.event){+.+.}, at: [<ffffffff822a055e>] > submit_bio_wait+0x15e/0x200 block/bio.c:953 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #4 ((complete)&ret.event){+.+.}: > check_prevs_add kernel/locking/lockdep.c:2020 [inline] > validate_chain kernel/locking/lockdep.c:2469 [inline] > __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 > lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 > complete_acquire include/linux/completion.h:39 [inline] > __wait_for_common kernel/sched/completion.c:108 [inline] > wait_for_common_io kernel/sched/completion.c:128 [inline] > wait_for_completion_io+0xc8/0x770 kernel/sched/completion.c:176 > submit_bio_wait+0x15e/0x200 block/bio.c:953 > blkdev_issue_zeroout+0x13c/0x1d0 block/blk-lib.c:370 > sb_issue_zeroout include/linux/blkdev.h:1367 [inline] > ext4_init_inode_table+0x4fd/0xdb1 fs/ext4/ialloc.c:1447 > ext4_run_li_request fs/ext4/super.c:2867 [inline] > ext4_lazyinit_thread+0x81a/0xd40 fs/ext4/super.c:2961 > kthread+0x39c/0x470 kernel/kthread.c:231 > ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 > > -> #3 (&meta_group_info[i]->alloc_sem){++++}: > check_prevs_add kernel/locking/lockdep.c:2020 [inline] > validate_chain kernel/locking/lockdep.c:2469 [inline] > __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 > lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 > down_read+0x96/0x150 kernel/locking/rwsem.c:23 > __ext4_new_inode+0x26dc/0x4f00 fs/ext4/ialloc.c:1056 > ext4_symlink+0x2d9/0xae0 fs/ext4/namei.c:3118 > vfs_symlink+0x323/0x560 fs/namei.c:4116 > SYSC_symlinkat fs/namei.c:4143 [inline] > SyS_symlinkat fs/namei.c:4123 [inline] > SYSC_symlink fs/namei.c:4156 [inline] > SyS_symlink+0x134/0x200 fs/namei.c:4154 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > -> #2 (jbd2_handle){.+.+}: > check_prevs_add kernel/locking/lockdep.c:2020 [inline] > validate_chain kernel/locking/lockdep.c:2469 [inline] > __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 > lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 > start_this_handle+0x4b8/0x1080 fs/jbd2/transaction.c:390 > jbd2__journal_start+0x389/0x9f0 fs/jbd2/transaction.c:444 > __ext4_journal_start_sb+0x15f/0x550 fs/ext4/ext4_jbd2.c:80 > __ext4_journal_start fs/ext4/ext4_jbd2.h:314 [inline] > ext4_dirty_inode+0x56/0xa0 fs/ext4/inode.c:5859 > __mark_inode_dirty+0x912/0x1170 fs/fs-writeback.c:2096 > generic_update_time+0x1b2/0x270 fs/inode.c:1649 > update_time fs/inode.c:1665 [inline] > touch_atime+0x26d/0x2f0 fs/inode.c:1737 > file_accessed include/linux/fs.h:2036 [inline] > ext4_file_mmap+0x161/0x1b0 fs/ext4/file.c:350 > call_mmap include/linux/fs.h:1748 [inline] > mmap_region+0xa99/0x15a0 mm/mmap.c:1690 > do_mmap+0x6a1/0xd50 mm/mmap.c:1468 > do_mmap_pgoff include/linux/mm.h:2150 [inline] > vm_mmap_pgoff+0x1de/0x280 mm/util.c:333 > SYSC_mmap_pgoff mm/mmap.c:1518 [inline] > SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1476 > SYSC_mmap arch/x86/kernel/sys_x86_64.c:99 [inline] > SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:90 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > -> #1 (&mm->mmap_sem){++++}: > check_prevs_add kernel/locking/lockdep.c:2020 [inline] > validate_chain kernel/locking/lockdep.c:2469 [inline] > __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 > lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 > __might_fault+0x13a/0x1d0 mm/memory.c:4502 > _copy_to_user+0x2c/0xc0 lib/usercopy.c:24 > copy_to_user include/linux/uaccess.h:154 [inline] > filldir+0x1a7/0x320 fs/readdir.c:196 > dir_emit_dot include/linux/fs.h:3314 [inline] > dir_emit_dots include/linux/fs.h:3325 [inline] > dcache_readdir+0x12d/0x5e0 fs/libfs.c:192 > iterate_dir+0x4b2/0x5d0 fs/readdir.c:51 > SYSC_getdents fs/readdir.c:231 [inline] > SyS_getdents+0x225/0x450 fs/readdir.c:212 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > -> #0 (&sb->s_type->i_mutex_key#9){++++}: > down_write+0x87/0x120 kernel/locking/rwsem.c:53 > inode_lock include/linux/fs.h:712 [inline] > generic_file_write_iter+0xdc/0x7a0 mm/filemap.c:3151 > call_write_iter include/linux/fs.h:1743 [inline] > do_iter_readv_writev+0x531/0x7f0 fs/read_write.c:650 > do_iter_write+0x15a/0x540 fs/read_write.c:929 > vfs_iter_write+0x77/0xb0 fs/read_write.c:942 > > other info that might help us debug this: > > Chain exists of: > &sb->s_type->i_mutex_key#9 --> &meta_group_info[i]->alloc_sem --> > (complete)&ret.event > > Possible unsafe locking scenario by crosslock: > > CPU0 CPU1 > ---- ---- > lock(&meta_group_info[i]->alloc_sem); > lock((complete)&ret.event); > lock(&sb->s_type->i_mutex_key#9); > unlock((complete)&ret.event); > > *** DEADLOCK *** > > 1 lock held by loop0/2986: > #0: (&x->wait#14){..-.}, at: [<ffffffff815263f8>] complete+0x18/0x80 > kernel/sched/completion.c:34 > > stack backtrace: > CPU: 1 PID: 2986 Comm: loop0 Not tainted 4.13.0+ #84 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:16 [inline] > dump_stack+0x194/0x257 lib/dump_stack.c:52 > print_circular_bug+0x503/0x710 kernel/locking/lockdep.c:1259 > check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894 > commit_xhlock kernel/locking/lockdep.c:5015 [inline] > commit_xhlocks kernel/locking/lockdep.c:5059 [inline] > lock_commit_crosslock+0xe73/0x1d10 kernel/locking/lockdep.c:5098 > complete_release_commit include/linux/completion.h:49 [inline] > complete+0x24/0x80 kernel/sched/completion.c:39 > submit_bio_wait_endio+0x9c/0xd0 block/bio.c:930 > bio_endio+0x2f8/0x8d0 block/bio.c:1843 > req_bio_endio block/blk-core.c:204 [inline] > blk_update_request+0x2a6/0xe20 block/blk-core.c:2743 > blk_mq_end_request+0x54/0x120 block/blk-mq.c:509 > lo_complete_rq+0xbe/0x1f0 drivers/block/loop.c:463 > __blk_mq_complete_request+0x38f/0x6c0 block/blk-mq.c:550 > blk_mq_complete_request+0x4f/0x60 block/blk-mq.c:570 > loop_handle_cmd drivers/block/loop.c:1710 [inline] > loop_queue_work+0x26b/0x3900 drivers/block/loop.c:1719 > kthread_worker_fn+0x340/0x9b0 kernel/kthread.c:635 This also happens on more recent commits. E.g. on upstream 42b76d0e6b1fe0fcb90e0ff6b4d053d50597b031: ====================================================== WARNING: possible circular locking dependency detected 4.14.0-rc3+ #116 Not tainted ------------------------------------------------------ loop6/10331 is trying to acquire lock: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff818756bc>] inode_lock include/linux/fs.h:712 [inline] (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff818756bc>] generic_file_write_iter+0xdc/0x7a0 mm/filemap.c:3175 but now in release context of a crosslock acquired at the following: ((complete)&ret.event){+.+.}, at: [<ffffffff822ac9fe>] submit_bio_wait+0x15e/0x200 block/bio.c:953 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 ((complete)&ret.event){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 complete_acquire include/linux/completion.h:39 [inline] __wait_for_common kernel/sched/completion.c:108 [inline] wait_for_common_io kernel/sched/completion.c:128 [inline] wait_for_completion_io+0xcb/0x7b0 kernel/sched/completion.c:176 submit_bio_wait+0x15e/0x200 block/bio.c:953 blkdev_issue_zeroout+0x13c/0x1d0 block/blk-lib.c:370 sb_issue_zeroout include/linux/blkdev.h:1368 [inline] ext4_init_inode_table+0x4fd/0xdb1 fs/ext4/ialloc.c:1447 ext4_run_li_request fs/ext4/super.c:2866 [inline] ext4_lazyinit_thread+0x808/0xd30 fs/ext4/super.c:2960 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #3 (&meta_group_info[i]->alloc_sem){++++}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 down_read+0x96/0x150 kernel/locking/rwsem.c:23 __ext4_new_inode+0x26dc/0x4f00 fs/ext4/ialloc.c:1056 ext4_symlink+0x2d9/0xae0 fs/ext4/namei.c:3118 vfs_symlink+0x323/0x560 fs/namei.c:4115 SYSC_symlinkat fs/namei.c:4142 [inline] SyS_symlinkat fs/namei.c:4122 [inline] SYSC_symlink fs/namei.c:4155 [inline] SyS_symlink+0x134/0x200 fs/namei.c:4153 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #2 (jbd2_handle){++++}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 start_this_handle+0x4b8/0x1080 fs/jbd2/transaction.c:390 jbd2__journal_start+0x389/0x9f0 fs/jbd2/transaction.c:444 __ext4_journal_start_sb+0x15f/0x550 fs/ext4/ext4_jbd2.c:80 __ext4_journal_start fs/ext4/ext4_jbd2.h:314 [inline] ext4_dirty_inode+0x56/0xa0 fs/ext4/inode.c:5859 __mark_inode_dirty+0x912/0x1170 fs/fs-writeback.c:2096 generic_update_time+0x1b2/0x270 fs/inode.c:1649 update_time fs/inode.c:1665 [inline] touch_atime+0x26d/0x2f0 fs/inode.c:1737 file_accessed include/linux/fs.h:2061 [inline] ext4_file_mmap+0x161/0x1b0 fs/ext4/file.c:352 call_mmap include/linux/fs.h:1775 [inline] mmap_region+0xa99/0x15a0 mm/mmap.c:1690 do_mmap+0x6a1/0xd50 mm/mmap.c:1468 do_mmap_pgoff include/linux/mm.h:2150 [inline] vm_mmap_pgoff+0x1de/0x280 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1518 [inline] SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1476 SYSC_mmap arch/x86/kernel/sys_x86_64.c:99 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:90 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #1 (&mm->mmap_sem){++++}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __might_fault+0x13a/0x1d0 mm/memory.c:4502 _copy_to_user+0x2c/0xc0 lib/usercopy.c:24 copy_to_user include/linux/uaccess.h:154 [inline] filldir+0x1a7/0x320 fs/readdir.c:196 dir_emit_dot include/linux/fs.h:3339 [inline] dir_emit_dots include/linux/fs.h:3350 [inline] dcache_readdir+0x12d/0x5e0 fs/libfs.c:192 iterate_dir+0x4b2/0x5d0 fs/readdir.c:51 SYSC_getdents fs/readdir.c:231 [inline] SyS_getdents+0x225/0x450 fs/readdir.c:212 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #0 (&sb->s_type->i_mutex_key#9){++++}: down_write+0x87/0x120 kernel/locking/rwsem.c:53 inode_lock include/linux/fs.h:712 [inline] generic_file_write_iter+0xdc/0x7a0 mm/filemap.c:3175 call_write_iter include/linux/fs.h:1770 [inline] do_iter_readv_writev+0x531/0x7f0 fs/read_write.c:673 do_iter_write+0x15a/0x540 fs/read_write.c:952 vfs_iter_write+0x77/0xb0 fs/read_write.c:965 > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkaller@xxxxxxxxxxxxxxxx. > Please credit me with: Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx> > > syzbot will keep track of this bug report. > Once a fix for this bug is committed, please reply to this email with: > #syz fix: exact-commit-title > To mark this as a duplicate of another syzbot report, please reply with: > #syz dup: exact-subject-of-another-report > If it's a one-off invalid bug report, please reply with: > #syz invalid > Note: if the crash happens again, it will cause creation of a new bug > report. > Note: all commands must start from beginning of the line. > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/94eb2c05f6a018dc21055d39c05b%40google.com. > For more options, visit https://groups.google.com/d/optout.
