From: Mike Galbraith <efault@gmx.de>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: tglx@linutronix.de, linux-rt-users@vger.kernel.org,
lkml <linux-kernel@vger.kernel.org>
Subject: [RT] 5.9-rt14 softirq_ctrl.lock vs listening_hash[i].lock lockdep splat
Date: Sat, 10 Oct 2020 06:31:57 +0200 [thread overview]
Message-ID: <12d6f9879a97cd56c09fb53dee343cbb14f7f1f7.camel@gmx.de> (raw)
[ 47.844511] ======================================================
[ 47.844511] WARNING: possible circular locking dependency detected
[ 47.844512] 5.9.0.gc85fb28-rt14-rt #1 Tainted: G E
[ 47.844513] ------------------------------------------------------
[ 47.844514] perl/2751 is trying to acquire lock:
[ 47.844515] ffff92cadec5a410 ((softirq_ctrl.lock).lock){+.+.}-{2:2}, at: __local_bh_disable_ip+0x127/0x2c0
[ 47.844521]
but task is already holding lock:
[ 47.844522] ffffffffa8871468 (&h->listening_hash[i].lock){+.+.}-{0:0}, at: listening_get_next.isra.41+0xd7/0x130
[ 47.844528]
which lock already depends on the new lock.
[ 47.844528]
the existing dependency chain (in reverse order) is:
[ 47.844529]
-> #1 (&h->listening_hash[i].lock){+.+.}-{0:0}:
[ 47.844532] rt_spin_lock+0x2b/0xc0
[ 47.844536] __inet_hash+0x68/0x320
[ 47.844539] inet_hash+0x31/0x60
[ 47.844541] inet_csk_listen_start+0xaf/0xe0
[ 47.844543] inet_listen+0x86/0x150
[ 47.844546] __sys_listen+0x58/0x80
[ 47.844548] __x64_sys_listen+0x12/0x20
[ 47.844549] do_syscall_64+0x33/0x40
[ 47.844552] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 47.844555]
-> #0 ((softirq_ctrl.lock).lock){+.+.}-{2:2}:
[ 47.844557] __lock_acquire+0x1343/0x1890
[ 47.844560] lock_acquire+0x92/0x410
[ 47.844562] rt_spin_lock+0x2b/0xc0
[ 47.844564] __local_bh_disable_ip+0x127/0x2c0
[ 47.844566] sock_i_ino+0x22/0x60
[ 47.844569] tcp4_seq_show+0x14f/0x420
[ 47.844571] seq_read+0x27c/0x420
[ 47.844574] proc_reg_read+0x5c/0x80
[ 47.844576] vfs_read+0xd1/0x1d0
[ 47.844580] ksys_read+0x87/0xc0
[ 47.844581] do_syscall_64+0x33/0x40
[ 47.844583] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 47.844585]
other info that might help us debug this:
[ 47.844585] Possible unsafe locking scenario:
[ 47.844586] CPU0 CPU1
[ 47.844586] ---- ----
[ 47.844587] lock(&h->listening_hash[i].lock);
[ 47.844588] lock((softirq_ctrl.lock).lock);
[ 47.844588] lock(&h->listening_hash[i].lock);
[ 47.844589] lock((softirq_ctrl.lock).lock);
[ 47.844590]
*** DEADLOCK ***
[ 47.844590] 3 locks held by perl/2751:
[ 47.844591] #0: ffff92ca6525a4e0 (&p->lock){+.+.}-{0:0}, at: seq_read+0x37/0x420
[ 47.844594] #1: ffffffffa8871468 (&h->listening_hash[i].lock){+.+.}-{0:0}, at: listening_get_next.isra.41+0xd7/0x130
[ 47.844597] #2: ffffffffa74b90e0 (rcu_read_lock){....}-{1:2}, at: rt_spin_lock+0x5/0xc0
[ 47.844600]
stack backtrace:
[ 47.844601] CPU: 1 PID: 2751 Comm: perl Kdump: loaded Tainted: G E 5.9.0.gc85fb28-rt14-rt #1
[ 47.844603] Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.20C 09/23/2013
[ 47.844604] Call Trace:
[ 47.844606] dump_stack+0x77/0x9b
[ 47.844611] check_noncircular+0x148/0x160
[ 47.844616] ? __lock_acquire+0x1343/0x1890
[ 47.844617] __lock_acquire+0x1343/0x1890
[ 47.844621] lock_acquire+0x92/0x410
[ 47.844623] ? __local_bh_disable_ip+0x127/0x2c0
[ 47.844626] ? sock_i_ino+0x5/0x60
[ 47.844628] rt_spin_lock+0x2b/0xc0
[ 47.844630] ? __local_bh_disable_ip+0x127/0x2c0
[ 47.844631] __local_bh_disable_ip+0x127/0x2c0
[ 47.844634] sock_i_ino+0x22/0x60
[ 47.844635] tcp4_seq_show+0x14f/0x420
[ 47.844640] seq_read+0x27c/0x420
[ 47.844643] proc_reg_read+0x5c/0x80
[ 47.844645] vfs_read+0xd1/0x1d0
[ 47.844648] ksys_read+0x87/0xc0
[ 47.844649] ? lockdep_hardirqs_on+0x78/0x100
[ 47.844652] do_syscall_64+0x33/0x40
[ 47.844654] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 47.844656] RIP: 0033:0x7fb3f3c23e51
[ 47.844658] Code: 7d 81 20 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb ba 0f 1f 80 00 00 00 00 8b 05 1a c3 20 00 48 63 ff 85 c0 75 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 57 f3 c3 0f 1f 44 00 00 55 53 48 89 d5 48 89
[ 47.844660] RSP: 002b:00007ffd7604f108 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 47.844661] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb3f3c23e51
[ 47.844662] RDX: 0000000000002000 RSI: 000055dbff4da600 RDI: 0000000000000003
[ 47.844662] RBP: 0000000000002000 R08: 000055dbff4d9290 R09: 000055dbff4da600
[ 47.844663] R10: ffffffffffffffb0 R11: 0000000000000246 R12: 000055dbff4da600
[ 47.844664] R13: 000055dbff4ae260 R14: 000055dbff4d92c0 R15: 0000000000000003
next reply other threads:[~2020-10-10 4:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-10 4:31 Mike Galbraith [this message]
2020-10-12 16:45 ` Sebastian Andrzej Siewior
2020-10-12 18:34 ` Mike Galbraith
2020-10-13 3:00 ` Mike Galbraith
2020-10-14 10:22 ` Sebastian Andrzej Siewior
2020-12-09 10:05 ` Peter Zijlstra
2020-12-09 10:25 ` Mike Galbraith
2020-12-09 10:32 ` Sebastian Andrzej Siewior
2020-12-09 11:47 ` Sebastian Andrzej Siewior
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