Re: possible deadlock in vprintk_emit

From: Dmitry Vyukov
Date: Fri Jun 08 2018 - 03:50:41 EST

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In reply to: syzbot: "possible deadlock in vprintk_emit"
Next in thread: Sergey Senozhatsky: "Re: possible deadlock in vprintk_emit"
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On Fri, Jun 8, 2018 at 9:38 AM, syzbot
<syzbot+831ee52a258e90882b4d@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 1c8c5a9d38f6 Merge git://git.kernel.org/pub/scm/linux/kern..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=131d4ddf800000
> kernel config: https://syzkaller.appspot.com/x/.config?x=4f1acdf888c9d4e9
> dashboard link: https://syzkaller.appspot.com/bug?extid=831ee52a258e90882b4d
> 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+831ee52a258e90882b4d@xxxxxxxxxxxxxxxxxxxxxxxxx

This is the same as that one, right?

#syz dup: possible deadlock in console_unlock

https://syzkaller.appspot.com/bug?id=39ea6caa479af471183997376dc7e90bc7d64a6a

> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000016
> R13: 00000000004be500 R14: 00000000004ccad8 R15: 0000000000000000
> CPU: 0 PID: 19202 Comm: syz-executor2 Not tainted 4.17.0+ #89
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 4.17.0+ #89 Not tainted
> ------------------------------------------------------
> syz-executor6/19187 is trying to acquire lock:
> 000000006e810651 (console_owner){-.-.}, at: console_trylock_spinning
> kernel/printk/printk.c:1651 [inline]
> 000000006e810651 (console_owner){-.-.}, at: vprintk_emit+0x826/0xde0
> kernel/printk/printk.c:1906
>
> but task is already holding lock:
> 000000004ec3be2c (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf9/0x1f0
> drivers/tty/pty.c:119
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #2 (&(&port->lock)->rlock){-.-.}:
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
> tty_port_tty_get+0x20/0x80 drivers/tty/tty_port.c:288
> tty_port_default_wakeup+0x15/0x40 drivers/tty/tty_port.c:47
> tty_port_tty_wakeup+0x5d/0x70 drivers/tty/tty_port.c:390
> uart_write_wakeup+0x44/0x60 drivers/tty/serial/serial_core.c:103
> serial8250_tx_chars+0x4be/0xb60
> drivers/tty/serial/8250/8250_port.c:1808
> serial8250_handle_irq.part.25+0x1ee/0x280
> drivers/tty/serial/8250/8250_port.c:1881
> serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1867
> [inline]
> serial8250_default_handle_irq+0xc8/0x150
> drivers/tty/serial/8250/8250_port.c:1897
> serial8250_interrupt+0xfa/0x1d0
> drivers/tty/serial/8250/8250_core.c:125
> __handle_irq_event_percpu+0x1c0/0xad0 kernel/irq/handle.c:149
> handle_irq_event_percpu+0x98/0x1c0 kernel/irq/handle.c:189
> handle_irq_event+0xa7/0x135 kernel/irq/handle.c:206
> handle_edge_irq+0x20f/0x870 kernel/irq/chip.c:791
> generic_handle_irq_desc include/linux/irqdesc.h:159 [inline]
> handle_irq+0x18c/0x2e7 arch/x86/kernel/irq_64.c:77
> do_IRQ+0x78/0x190 arch/x86/kernel/irq.c:245
> ret_from_intr+0x0/0x1e
> native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
> arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
> default_idle+0xc2/0x440 arch/x86/kernel/process.c:500
> arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:491
> default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
> cpuidle_idle_call kernel/sched/idle.c:153 [inline]
> do_idle+0x395/0x560 kernel/sched/idle.c:262
> cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:368
> start_secondary+0x42b/0x5c0 arch/x86/kernel/smpboot.c:265
> secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242
>
> -> #1 (&port_lock_key){-.-.}:
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
> serial8250_console_write+0x8d5/0xb00
> drivers/tty/serial/8250/8250_port.c:3230
> univ8250_console_write+0x5f/0x70
> drivers/tty/serial/8250/8250_core.c:590
> call_console_drivers kernel/printk/printk.c:1718 [inline]
> console_unlock+0xa9d/0x10a0 kernel/printk/printk.c:2389
> vprintk_emit+0x6b2/0xde0 kernel/printk/printk.c:1907
> vprintk_default+0x28/0x30 kernel/printk/printk.c:1948
> vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382
> printk+0x9e/0xba kernel/printk/printk.c:1981
> register_console+0x7e7/0xc00 kernel/printk/printk.c:2704
> univ8250_console_init+0x3f/0x4b
> drivers/tty/serial/8250/8250_core.c:685
> console_init+0x6d9/0xa38 kernel/printk/printk.c:2788
> start_kernel+0x608/0x92d init/main.c:661
> x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
> x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
> secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242
>
> -> #0 (console_owner){-.-.}:
> lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3924
> console_trylock_spinning kernel/printk/printk.c:1672 [inline]
> vprintk_emit+0x884/0xde0 kernel/printk/printk.c:1906
> vprintk_default+0x28/0x30 kernel/printk/printk.c:1948
> vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382
> printk+0x9e/0xba kernel/printk/printk.c:1981
> fail_dump lib/fault-inject.c:44 [inline]
> should_fail+0x97a/0xbcd lib/fault-inject.c:149
> __should_failslab+0x124/0x180 mm/failslab.c:32
> should_failslab+0x9/0x14 mm/slab_common.c:1522
> slab_pre_alloc_hook mm/slab.h:423 [inline]
> slab_alloc mm/slab.c:3378 [inline]
> __do_kmalloc mm/slab.c:3716 [inline]
> __kmalloc+0x63/0x760 mm/slab.c:3727
> kmalloc include/linux/slab.h:518 [inline]
> tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline]
> __tty_buffer_request_room+0x2d2/0x7f0 drivers/tty/tty_buffer.c:268
> tty_insert_flip_string_fixed_flag+0x8d/0x1f0
> drivers/tty/tty_buffer.c:313
> tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
> pty_write+0x12c/0x1f0 drivers/tty/pty.c:121
> tty_put_char+0x129/0x150 drivers/tty/tty_io.c:2865
> __process_echoes+0x4d9/0x8d0 drivers/tty/n_tty.c:703
> process_echoes+0xfc/0x170 drivers/tty/n_tty.c:781
> n_tty_set_termios+0xb56/0xe80 drivers/tty/n_tty.c:1837
> tty_set_termios+0x7a0/0xac0 drivers/tty/tty_ioctl.c:341
> set_termios+0x41e/0x7d0 drivers/tty/tty_ioctl.c:414
> tty_mode_ioctl+0x535/0xb50 drivers/tty/tty_ioctl.c:747
> n_tty_ioctl_helper+0x54/0x3b0 drivers/tty/tty_ioctl.c:940
> n_tty_ioctl+0x54/0x320 drivers/tty/n_tty.c:2441
> tty_ioctl+0x5e1/0x1870 drivers/tty/tty_io.c:2655
> vfs_ioctl fs/ioctl.c:46 [inline]
> file_ioctl fs/ioctl.c:500 [inline]
> do_vfs_ioctl+0x1cf/0x16f0 fs/ioctl.c:684
> ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
> __do_sys_ioctl fs/ioctl.c:708 [inline]
> __se_sys_ioctl fs/ioctl.c:706 [inline]
> __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
> do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> other info that might help us debug this:
>
> Chain exists of:
> console_owner --> &port_lock_key --> &(&port->lock)->rlock
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(&(&port->lock)->rlock);
> lock(&port_lock_key);
> lock(&(&port->lock)->rlock);
> lock(console_owner);
>
> *** DEADLOCK ***
>
> 5 locks held by syz-executor6/19187:
> #0: 000000007080a3ba (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40
> drivers/tty/tty_ldsem.c:365
> #1: 000000006fe00659 (&o_tty->termios_rwsem/1){++++}, at:
> tty_set_termios+0xfd/0xac0 drivers/tty/tty_ioctl.c:328
> #2: 000000007080a3ba (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x22/0x90
> drivers/tty/tty_ldisc.c:284
> #3: 00000000f8d1ab16 (&ldata->output_lock){+.+.}, at:
> process_echoes+0xb6/0x170 drivers/tty/n_tty.c:779
> #4: 000000004ec3be2c (&(&port->lock)->rlock){-.-.}, at:
> pty_write+0xf9/0x1f0 drivers/tty/pty.c:119
>
> stack backtrace:
> CPU: 1 PID: 19187 Comm: syz-executor6 Not tainted 4.17.0+ #89
> 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+0x1b9/0x294 lib/dump_stack.c:113
> print_circular_bug.isra.36.cold.56+0x1bd/0x27d
> kernel/locking/lockdep.c:1227
> check_prev_add kernel/locking/lockdep.c:1867 [inline]
> check_prevs_add kernel/locking/lockdep.c:1980 [inline]
> validate_chain kernel/locking/lockdep.c:2421 [inline]
> __lock_acquire+0x343e/0x5140 kernel/locking/lockdep.c:3435
> lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3924
> console_trylock_spinning kernel/printk/printk.c:1672 [inline]
> vprintk_emit+0x884/0xde0 kernel/printk/printk.c:1906
> vprintk_default+0x28/0x30 kernel/printk/printk.c:1948
> vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382
> printk+0x9e/0xba kernel/printk/printk.c:1981
> fail_dump lib/fault-inject.c:44 [inline]
> should_fail+0x97a/0xbcd lib/fault-inject.c:149
> __should_failslab+0x124/0x180 mm/failslab.c:32
> should_failslab+0x9/0x14 mm/slab_common.c:1522
> slab_pre_alloc_hook mm/slab.h:423 [inline]
> slab_alloc mm/slab.c:3378 [inline]
> __do_kmalloc mm/slab.c:3716 [inline]
> __kmalloc+0x63/0x760 mm/slab.c:3727
> kmalloc include/linux/slab.h:518 [inline]
> tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline]
> __tty_buffer_request_room+0x2d2/0x7f0 drivers/tty/tty_buffer.c:268
> tty_insert_flip_string_fixed_flag+0x8d/0x1f0 drivers/tty/tty_buffer.c:313
> tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
> pty_write+0x12c/0x1f0 drivers/tty/pty.c:121
> tty_put_char+0x129/0x150 drivers/tty/tty_io.c:2865
> __process_echoes+0x4d9/0x8d0 drivers/tty/n_tty.c:703
> process_echoes+0xfc/0x170 drivers/tty/n_tty.c:781
> n_tty_set_termios+0xb56/0xe80 drivers/tty/n_tty.c:1837
> tty_set_termios+0x7a0/0xac0 drivers/tty/tty_ioctl.c:341
> set_termios+0x41e/0x7d0 drivers/tty/tty_ioctl.c:414
> tty_mode_ioctl+0x535/0xb50 drivers/tty/tty_ioctl.c:747
> n_tty_ioctl_helper+0x54/0x3b0 drivers/tty/tty_ioctl.c:940
> n_tty_ioctl+0x54/0x320 drivers/tty/n_tty.c:2441
> tty_ioctl+0x5e1/0x1870 drivers/tty/tty_io.c:2655
> vfs_ioctl fs/ioctl.c:46 [inline]
> file_ioctl fs/ioctl.c:500 [inline]
> do_vfs_ioctl+0x1cf/0x16f0 fs/ioctl.c:684
> ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
> __do_sys_ioctl fs/ioctl.c:708 [inline]
> __se_sys_ioctl fs/ioctl.c:706 [inline]
> __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
> do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x4559f9
> Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
> 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff
> Lost 23 message(s)!
> IPVS: length: 236 != 24
> 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+0x1b9/0x294 lib/dump_stack.c:113
> IPVS: length: 236 != 24
> fail_dump lib/fault-inject.c:51 [inline]
> should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149
> __should_failslab+0x124/0x180 mm/failslab.c:32
> should_failslab+0x9/0x14 mm/slab_common.c:1522
> slab_pre_alloc_hook mm/slab.h:423 [inline]
> slab_alloc_node mm/slab.c:3299 [inline]
> kmem_cache_alloc_node_trace+0x26f/0x770 mm/slab.c:3661
> __do_kmalloc_node mm/slab.c:3681 [inline]
> __kmalloc_node_track_caller+0x33/0x70 mm/slab.c:3696
> __kmalloc_reserve.isra.39+0x3a/0xe0 net/core/skbuff.c:137
> __alloc_skb+0x14d/0x780 net/core/skbuff.c:205
> alloc_skb include/linux/skbuff.h:987 [inline]
> netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
> netlink_sendmsg+0xb01/0xfa0 net/netlink/af_netlink.c:1876
> sock_sendmsg_nosec net/socket.c:633 [inline]
> sock_sendmsg+0xd5/0x120 net/socket.c:643
> ___sys_sendmsg+0x805/0x940 net/socket.c:2149
> __sys_sendmsg+0x115/0x270 net/socket.c:2187
> __do_sys_sendmsg net/socket.c:2196 [inline]
> __se_sys_sendmsg net/socket.c:2194 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2194
> do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x4559f9
> Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
> 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff
> 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007fe47fbe2c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007fe47fbe36d4 RCX: 00000000004559f9
> RDX: 0000000000000000 RSI: 0000000020000900 RDI: 0000000000000014
> RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000015
> R13: 00000000004c08de R14: 00000000004d00d8 R15: 0000000000000001
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> nla_parse: 5 callbacks suppressed
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
> netlink: 8 bytes leftover after parsing attributes in process
> `syz-executor2'.
>
>
> ---
> 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@xxxxxxxxxxxxxxxxx
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
> syzbot.
>
> --
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Next message: Linus Walleij: "Re: [PATCH] ARM: pxa, regulator: fix building ezx e680"
Previous message: Jia He: "[PATCH v2] crypto: arm64/aes-blk - fix and move skcipher_walk_done out of kernel_neon_begin,_end"
In reply to: syzbot: "possible deadlock in vprintk_emit"
Next in thread: Sergey Senozhatsky: "Re: possible deadlock in vprintk_emit"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]