d4d5d8e83c
Before thread in process context uses bh_lock_sock() we must disable bh. sysbot reported : WARNING: inconsistent lock state 5.2.0-rc3+ #32 Not tainted inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. blkid/26581 [HC0[0]:SC1[1]:HE1:SE0] takes: 00000000e0da85ee (slock-AF_AX25){+.?.}, at: spin_lock include/linux/spinlock.h:338 [inline] 00000000e0da85ee (slock-AF_AX25){+.?.}, at: ax25_destroy_timer+0x53/0xc0 net/ax25/af_ax25.c:275 {SOFTIRQ-ON-W} state was registered at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] ax25_rt_autobind+0x3ca/0x720 net/ax25/ax25_route.c:429 ax25_connect.cold+0x30/0xa4 net/ax25/af_ax25.c:1221 __sys_connect+0x264/0x330 net/socket.c:1834 __do_sys_connect net/socket.c:1845 [inline] __se_sys_connect net/socket.c:1842 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1842 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe irq event stamp: 2272 hardirqs last enabled at (2272): [<ffffffff810065f3>] trace_hardirqs_on_thunk+0x1a/0x1c hardirqs last disabled at (2271): [<ffffffff8100660f>] trace_hardirqs_off_thunk+0x1a/0x1c softirqs last enabled at (1522): [<ffffffff87400654>] __do_softirq+0x654/0x94c kernel/softirq.c:320 softirqs last disabled at (2267): [<ffffffff81449010>] invoke_softirq kernel/softirq.c:374 [inline] softirqs last disabled at (2267): [<ffffffff81449010>] irq_exit+0x180/0x1d0 kernel/softirq.c:414 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(slock-AF_AX25); <Interrupt> lock(slock-AF_AX25); *** DEADLOCK *** 1 lock held by blkid/26581: #0: 0000000010fd154d ((&ax25->dtimer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:175 [inline] #0: 0000000010fd154d ((&ax25->dtimer)){+.-.}, at: call_timer_fn+0xe0/0x720 kernel/time/timer.c:1312 stack backtrace: CPU: 1 PID: 26581 Comm: blkid Not tainted 5.2.0-rc3+ #32 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_usage_bug.cold+0x393/0x4a2 kernel/locking/lockdep.c:2935 valid_state kernel/locking/lockdep.c:2948 [inline] mark_lock_irq kernel/locking/lockdep.c:3138 [inline] mark_lock+0xd46/0x1370 kernel/locking/lockdep.c:3513 mark_irqflags kernel/locking/lockdep.c:3391 [inline] __lock_acquire+0x159f/0x5490 kernel/locking/lockdep.c:3745 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] ax25_destroy_timer+0x53/0xc0 net/ax25/af_ax25.c:275 call_timer_fn+0x193/0x720 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x66f/0x1740 kernel/time/timer.c:1698 __do_softirq+0x25c/0x94c kernel/softirq.c:293 invoke_softirq kernel/softirq.c:374 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:414 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 </IRQ> RIP: 0033:0x7f858d5c3232 Code: 8b 61 08 48 8b 84 24 d8 00 00 00 4c 89 44 24 28 48 8b ac 24 d0 00 00 00 4c 8b b4 24 e8 00 00 00 48 89 7c 24 68 48 89 4c 24 78 <48> 89 44 24 58 8b 84 24 e0 00 00 00 89 84 24 84 00 00 00 8b 84 24 RSP: 002b:00007ffcaf0cf5c0 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 RAX: 00007f858d7d27a8 RBX: 00007f858d7d8820 RCX: 00007f858d3940d8 RDX: 00007ffcaf0cf798 RSI: 00000000f5e616f3 RDI: 00007f858d394fee RBP: 0000000000000000 R08: 00007ffcaf0cf780 R09: 00007f858d7db480 R10: 0000000000000000 R11: 0000000009691a75 R12: 0000000000000005 R13: 00000000f5e616f3 R14: 0000000000000000 R15: 00007ffcaf0cf798 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.