syzbot


INFO: task hung in __fat_readdir

Status: auto-closed as invalid on 2019/02/22 12:36
First crash: 2073d, last: 2073d

Sample crash report:
pktgen: Cannot create thread for cpu 1 (-4)
pktgen: Initialization failed for all threads
INFO: task syz-executor0:20907 blocked for more than 140 seconds.
      Not tainted 4.9.119-g9dc978d #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D26200 20907  10557 0x00000004
 ffff88019b62b000 ffff8801ab78aa00 ffff8801ab78aa00 ffff8801b9e6e000
 ffff8801db221c18 ffff88019e73f9a8 ffffffff839ebdcd ffff88019b62b8c8
 ffffed00336c5718 ffff88019b62b000 00fffc0000000000 ffff8801db2224e8
Call Trace:
 [<ffffffff839ed3cf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839edd53>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff839f21d6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839f21d6>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff818c07a7>] __fat_readdir+0x1b7/0x1840 fs/fat/dir.c:570
 [<ffffffff818c1e71>] fat_readdir+0x41/0x50 fs/fat/dir.c:703
 [<ffffffff815b42fc>] iterate_dir+0x1ac/0x600 fs/readdir.c:50
 [<ffffffff815b533c>] SYSC_getdents fs/readdir.c:230 [inline]
 [<ffffffff815b533c>] SyS_getdents+0x13c/0x2a0 fs/readdir.c:211
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667bc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667bc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81426027>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/3662:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d859c>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157307e>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157307e>] vfs_write+0x3ae/0x530 fs/read_write.c:556
1 lock held by rsyslogd/3665:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d859c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3760:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fae72>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821208d2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
3 locks held by syz-executor0/20907:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d859c>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (&sb->s_type->i_mutex_key#21){++++++}, at: [<ffffffff815b4213>] inode_lock_shared include/linux/fs.h:776 [inline]
 #1:  (&sb->s_type->i_mutex_key#21){++++++}, at: [<ffffffff815b4213>] iterate_dir+0xc3/0x600 fs/readdir.c:39
 #2:  (&sbi->s_lock){+.+.+.}, at: [<ffffffff818c07a7>] __fat_readdir+0x1b7/0x1840 fs/fat/dir.c:570

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d842fd08 ffffffff81eb4be9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d842fd40
 ffffffff81ebfee7 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4be9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4be9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebfee7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebfe7a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366d54>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d54>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d54>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d54>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fce9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 20897 Comm: syz-executor0 Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019adb9800 task.stack: ffff88019c000000
RIP: 0010:[<ffffffff8122fbfb>] c [<ffffffff8122fbfb>] match_held_lock+0xb/0x570 kernel/locking/lockdep.c:3404
RSP: 0018:ffff88019c007758  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: ffff88019adb9800 RCX: 0000000000000000
RDX: 1ffff100335b7418 RSI: ffffffff846defa0 RDI: ffff88019adba0c8
RBP: ffff88019c007798 R08: ffff88019adba160 R09: 0000000000000001
R10: ffff88019adb9800 R11: 1ffff100335b7427 R12: ffffed00335b7418
R13: ffff88019adba0c8 R14: ffffffff846defa0 R15: 0000000000000000
FS:  00007f3e52ff5700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdf01a5c000 CR3: 00000001d004a000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff88019c007798c ffffffff81230202c ffff88019adba0c0c 0000000000000246c
 ffff88019adb9800c ffffffff846defa0c 0000000002420848c ffff8801d9c159c8c
 ffff88019c0077c0c ffffffff81230a34c ffffea000703ec40c ffff8801d9c290e8c
Call Trace:
 [<ffffffff81230a34>] lock_is_held+0xb4/0x140 kernel/locking/lockdep.c:3794
 [<ffffffff8127c244>] rcu_read_lock_held+0xa4/0xc0 kernel/rcu/update.c:297
 [<ffffffff814391bb>] radix_tree_deref_slot include/linux/radix-tree.h:199 [inline]
 [<ffffffff814391bb>] find_get_entry+0x34b/0x540 mm/filemap.c:1095
 [<ffffffff8143a2eb>] pagecache_get_page+0x4b/0x720 mm/filemap.c:1201
 [<ffffffff81625809>] find_or_create_page include/linux/pagemap.h:309 [inline]
 [<ffffffff81625809>] grow_dev_page fs/buffer.c:1005 [inline]
 [<ffffffff81625809>] grow_buffers fs/buffer.c:1078 [inline]
 [<ffffffff81625809>] __getblk_slow fs/buffer.c:1105 [inline]
 [<ffffffff81625809>] __getblk_gfp+0x249/0x710 fs/buffer.c:1386
 [<ffffffff816290ed>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818b78e8>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818b78e8>] fat__get_entry+0x4c8/0x8f0 fs/fat/dir.c:100
 [<ffffffff818c095c>] fat_get_entry fs/fat/dir.c:128 [inline]
 [<ffffffff818c095c>] __fat_readdir+0x36c/0x1840 fs/fat/dir.c:589
 [<ffffffff818c1e71>] fat_readdir+0x41/0x50 fs/fat/dir.c:703
 [<ffffffff815b42fc>] iterate_dir+0x1ac/0x600 fs/readdir.c:50
 [<ffffffff815b533c>] SYSC_getdents fs/readdir.c:230 [inline]
 [<ffffffff815b533c>] SyS_getdents+0x13c/0x2a0 fs/readdir.c:211
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: c55 c48 c89 cd1 c41 cb8 c01 c00 c00 c00 c48 cc7 cc2 c60 cdc c22 c81 c48 c89 ce5 ce8 cb7 cf9 cff cff c5d cc3 c0f c1f c44 c00 c00 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c55 c<48> c89 ce5 c41 c57 c41 c56 c41 c55 c49 c89 cfd c48 c83 cc7 c10 c48 c89 cfa c41 c54 c

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/08/11 14:47 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
* Struck through repros no longer work on HEAD.