On Mon, Jul 9, 2018 at 7:07 PM, syzbot <syzbot+9d0373cdac2be4979750@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 1e4b044d2251 Linux 4.18-rc4 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=14dc81b2400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=25856fac4e580aa7 > dashboard link: https://syzkaller.appspot.com/bug?extid=9d0373cdac2be4979750 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+9d0373cdac2be4979750@xxxxxxxxxxxxxxxxxxxxxxxxx This looks suspiciously similar to "INFO: task hung in vfs_setxattr": https://syzkaller.appspot.com/bug?id=719b006d5ff2c98e95b3db1d442771de9fcbfb93 Also caused by 9p program: 14:02:00 executing program 5: pipe2$9p(&(0x7f0000000100)={<r0=>0xffffffffffffffff, <r1=>0xffffffffffffffff}, 0x0) write$P9_RUNLINKAT(r1, &(0x7f0000000040)={0xffffffffffffffca, 0x4d}, 0x7) mkdir(&(0x7f0000000140)='./file0\x00', 0x0) mount$9p_fd(0x0, &(0x7f00000000c0)='./file0\x00', &(0x7f0000000340)='9p\x00', 0x0, &(0x7f00000001c0)={'trans=fd,', {'rfdno', 0x3d, r0}, 0x2c, {'wfdno', 0x3d, r1}, 0x2c}) write$P9_RREADDIR(r1, &(0x7f0000000480)={0x2a, 0x29, 0x1, {0x0, [{{}, 0x0, 0x0, 0x7, './file0'}]}}, 0x2a) write$P9_RGETATTR(r1, &(0x7f0000000200)={0xa0, 0x19, 0x1}, 0xa0) write$P9_RREADDIR(r1, &(0x7f00000004c0)={0x313, 0x29, 0x1, {0x0, [{{0x2, 0x3, 0x7}, 0x10001, 0x3, 0x7, './file0'}, {{0x1d, 0x4, 0x5}, 0x100000000, 0x8, 0x7, './file1'}, {{0x4, 0x2, 0x4}, 0x3, 0x6, 0x7, './file0'}, {{0x120, 0x2, 0x2}, 0x979, 0x4, 0x7, './file0'}, {{0x4f5f4daf2e09cfcf, 0x4, 0x6}, 0x1000, 0x1, 0x7, './file0'}, {{0x82, 0x1, 0x2}, 0x5, 0x2, 0x7, './file0'}, {{0x40, 0x1, 0x7}, 0x2, 0x6, 0x7, './file0'}, {{0x40, 0x1, 0x2}, 0x7fffffff, 0x983d, 0x7, './file0'}, {{0x40, 0x3, 0x4}, 0x2, 0x5, 0x7, './file0'}, {{0x60, 0x1, 0x3}, 0x7ff, 0x7, 0x7, './file0'}]}}, 0x141) r2 = openat$pfkey(0xffffffffffffff9c, &(0x7f0000000300)='/proc/self/net/pfkey\x00', 0x1, 0x0) bind(r2, &(0x7f0000000780)=@ethernet={0x306, @broadcast=[0xff, 0xff, 0xff, 0xff, 0xff, 0xff]}, 0x80) write$P9_RWSTAT(r1, &(0x7f00000002c0)={0x7, 0x7f, 0x1}, 0x7) mount$9p_fd(0x0, &(0x7f0000000000)='./file0\x00', &(0x7f0000000900)='9p\x00', 0x0, &(0x7f0000000840)={'trans=fd,', {'rfdno', 0x3d, r0}, 0x2c, {'wfdno', 0x3d, r1}, 0x2c, {[{@access_uid={'access', 0x3d}, 0x2c}]}}) removexattr(&(0x7f0000000380)='./file0\x00', &(0x7f0000000400)=@known='system.posix_acl_default\x00') r3 = syz_open_dev$midi(&(0x7f0000000080)='/dev/midi#\x00', 0x1ff, 0x400) r4 = fcntl$getown(r1, 0x9) accept4$alg(r2, 0x0, 0x0, 0x0) ioctl$SNDRV_CTL_IOCTL_ELEM_INFO(r3, 0xc1105511, &(0x7f0000000640)={{0x4, 0x1, 0x81, 0x5b94, '\x00', 0x3b2}, 0x2, 0x1, 0x90, r4, 0x3, 0x8, 'syz0\x00', &(0x7f0000000180)=['\x00', '+@,\x00', ')\x00'], 0x7, [], [0x6, 0x10000, 0x2, 0x8]}) > netlink: 16 bytes leftover after parsing attributes in process > `syz-executor0'. > netlink: 16 bytes leftover after parsing attributes in process > `syz-executor0'. > INFO: task syz-executor5:14548 blocked for more than 140 seconds. > Not tainted 4.18.0-rc4+ #138 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-executor5 D24752 14548 4547 0x00000004 > Call Trace: > context_switch kernel/sched/core.c:2853 [inline] > __schedule+0x87c/0x1ed0 kernel/sched/core.c:3501 > schedule+0xfb/0x450 kernel/sched/core.c:3545 > __rwsem_down_write_failed_common+0x95d/0x1630 > kernel/locking/rwsem-xadd.c:566 > rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 > call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 > __down_write arch/x86/include/asm/rwsem.h:142 [inline] > down_write+0xaa/0x130 kernel/locking/rwsem.c:72 > inode_lock include/linux/fs.h:715 [inline] > vfs_removexattr+0x82/0x1c0 fs/xattr.c:391 > removexattr+0xd3/0x130 fs/xattr.c:691 > path_removexattr+0x1b9/0x210 fs/xattr.c:705 > __do_sys_removexattr fs/xattr.c:719 [inline] > __se_sys_removexattr fs/xattr.c:716 [inline] > __x64_sys_removexattr+0x59/0x80 fs/xattr.c:716 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x455e29 > Code: cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 0f 86 ab 04 00 00 48 83 ec > 58 48 89 6c 24 50 48 8d 6c 24 50 48 8b 44 24 60 c6 00 00 <48> 8b 4c 24 68 48 > 89 ca 48 89 50 08 48 8b 59 20 48 01 da 31 db 31 > RSP: 002b:00007f4465180c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000c5 > RAX: ffffffffffffffda RBX: 00007f44651816d4 RCX: 0000000000455e29 > RDX: 0000000000000000 RSI: 0000000020000400 RDI: 0000000020000380 > RBP: 000000000072bf48 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000004bbfeb R14: 00000000004d1108 R15: 0000000000000001 > > Showing all locks held in the system: > 1 lock held by khungtaskd/901: > #0: 00000000ebf24c36 (rcu_read_lock){....}, at: > debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 > 1 lock held by rsyslogd/4405: > 2 locks held by getty/4495: > #0: 00000000692a9d2f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 0000000072fe5412 (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 > 2 locks held by getty/4496: > #0: 000000002b623882 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 0000000056c15f7c (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 > 2 locks held by getty/4497: > #0: 000000002c1f858b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 0000000048aba06b (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 > 2 locks held by getty/4498: > #0: 00000000da02f89a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 000000004a06c40f (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 > 2 locks held by getty/4499: > #0: 0000000017508207 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 00000000a4b24877 (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 > 2 locks held by getty/4500: > #0: 0000000079a247d3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 000000009bcfd45d (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 > 2 locks held by getty/4501: > #0: 00000000e73958a9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 000000007d96a629 (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 > 2 locks held by syz-executor5/14500: > #0: 00000000ba1ef7f9 (sb_writers#19){.+.+}, at: sb_start_write > include/linux/fs.h:1554 [inline] > #0: 00000000ba1ef7f9 (sb_writers#19){.+.+}, at: mnt_want_write+0x3f/0xc0 > fs/namespace.c:386 > #1: 00000000e4cbde96 (&sb->s_type->i_mutex_key#25){++++}, at: inode_lock > include/linux/fs.h:715 [inline] > #1: 00000000e4cbde96 (&sb->s_type->i_mutex_key#25){++++}, at: > vfs_removexattr+0x82/0x1c0 fs/xattr.c:391 > 2 locks held by syz-executor5/14548: > #0: 00000000ba1ef7f9 (sb_writers#19){.+.+}, at: sb_start_write > include/linux/fs.h:1554 [inline] > #0: 00000000ba1ef7f9 (sb_writers#19){.+.+}, at: mnt_want_write+0x3f/0xc0 > fs/namespace.c:386 > #1: 00000000e4cbde96 (&sb->s_type->i_mutex_key#25){++++}, at: inode_lock > include/linux/fs.h:715 [inline] > #1: 00000000e4cbde96 (&sb->s_type->i_mutex_key#25){++++}, at: > vfs_removexattr+0x82/0x1c0 fs/xattr.c:391 > > ============================================= > > NMI backtrace for cpu 0 > CPU: 0 PID: 901 Comm: khungtaskd Not tainted 4.18.0-rc4+ #138 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 > nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 > nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 > arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 > trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] > check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] > watchdog+0x9c4/0xf80 kernel/hung_task.c:252 > kthread+0x345/0x410 kernel/kthread.c:246 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > Sending NMI from CPU 0 to CPUs 1: > NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 > arch/x86/include/asm/irqflags.h:54 > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. > > -- > 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/000000000000cec1940570940acf%40google.com. > For more options, visit https://groups.google.com/d/optout.
