bisecting fixing commit since 7ca4ad5ba886557b67d42242a80f303c3a99ded1
building syzkaller on 9dcc1191cb8089742cc226a8b64f992ae505cc22
testing commit 7ca4ad5ba886557b67d42242a80f303c3a99ded1 with gcc (GCC) 8.1.0
kernel signature: 02bb6fe75673ee79ce933f8d319bbe20df7cf8119d6e32ce1cc563de0d1a2822
run #0: crashed: INFO: rcu detected stall in corrupted
run #1: crashed: INFO: rcu detected stall in new_sync_read
run #2: crashed: INFO: rcu detected stall in sys_open
run #3: crashed: INFO: rcu detected stall in corrupted
run #4: crashed: INFO: rcu detected stall in sys_open
run #5: crashed: INFO: rcu detected stall in sys_open
run #6: crashed: INFO: rcu detected stall in corrupted
run #7: crashed: INFO: rcu detected stall in corrupted
run #8: crashed: INFO: rcu detected stall in sys_open
run #9: crashed: INFO: rcu detected stall in sys_open
testing current HEAD 47ec5303d73ea344e84f46660fff693c57641386
testing commit 47ec5303d73ea344e84f46660fff693c57641386 with gcc (GCC) 8.1.0
kernel signature: 221cca6e679470c2a8094c0302efb4684bdfbeddf082f4da9aef3894678ff9ae
run #0: crashed: INFO: rcu detected stall in sys_open
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in corrupted
run #3: crashed: INFO: rcu detected stall in corrupted
run #4: crashed: INFO: rcu detected stall in corrupted
run #5: crashed: INFO: rcu detected stall in corrupted
run #6: crashed: INFO: rcu detected stall in corrupted
run #7: crashed: INFO: rcu detected stall in corrupted
run #8: crashed: INFO: rcu detected stall in sys_open
run #9: crashed: INFO: rcu detected stall in corrupted
revisions tested: 2, total time: 21m8.18254874s (build: 10m45.707476264s, test: 9m28.874093419s)
the crash still happens on HEAD
commit msg: Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
crash: INFO: rcu detected stall in corrupted
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=3641, q=399)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294952389-4294941886), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10504 jiffies! g3641 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    14264    10      2 0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x3f3/0x880 kernel/sched/core.c:4527
 schedule+0x3b/0xf0 kernel/sched/core.c:4602
 schedule_timeout+0x1ae/0x2d0 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1887 [inline]
 rcu_gp_kthread+0x702/0xc70 kernel/rcu/tree.c:2057
 kthread+0x160/0x180 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294