bisecting fixing commit since 2187f215ebaac73ddbd814696d7c7fa34f0c3de0
building syzkaller on 79b211f74b08737aeb4934c6ff69a263b3c38013
testing commit 2187f215ebaac73ddbd814696d7c7fa34f0c3de0 with gcc (GCC) 8.1.0
kernel signature: f5953f92f041a0d09055dfd6d79e5d57d712ee9f412a6a9a9717b9636d897b52
run #0: crashed: INFO: rcu detected stall in bad_area
run #1: crashed: INFO: rcu detected stall in bad_area
run #2: crashed: INFO: rcu detected stall in bad_area
run #3: crashed: INFO: rcu detected stall in do_signal
run #4: crashed: INFO: rcu detected stall in do_signal
run #5: crashed: INFO: rcu detected stall in do_signal
run #6: crashed: INFO: rcu detected stall in do_signal
run #7: crashed: INFO: rcu detected stall in bad_area
run #8: crashed: INFO: rcu detected stall in corrupted
run #9: crashed: INFO: rcu detected stall in bad_area
testing current HEAD 44b6e23be32be4470b1b8bf27380c2e9cca98e2b
testing commit 44b6e23be32be4470b1b8bf27380c2e9cca98e2b with gcc (GCC) 8.1.0
kernel signature: 9e2a6736a05b92d57787c4efcade8aa1f9690c17c7e168b1e33e839d81d0fdeb
all runs: crashed: INFO: rcu detected stall in corrupted
revisions tested: 2, total time: 22m18.519870756s (build: 11m41.388583536s, test: 9m35.860468396s)
the crash still happens on HEAD
commit msg: Merge tag 'iommu-fixes-v5.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
crash: INFO: rcu detected stall in corrupted
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=3945, q=575)
rcu: All QSes seen, last rcu_preempt kthread activity 10498 (4294951789-4294941291), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10498 jiffies! g3945 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:14272 pid:   10 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x404/0x8a0 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:1890 [inline]
 rcu_gp_kthread+0x702/0xc70 kernel/rcu/tree.c:2060
 kthread+0x160/0x180 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294