bisecting cause commit starting from b0314565da2b95e73feab484467ad171fcce6dff
building syzkaller on aa4feb03290ee285b276e5a9c9abddd5296e79e0
testing commit b0314565da2b95e73feab484467ad171fcce6dff with gcc (GCC) 8.1.0
run #0: OK
run #1: crashed: INFO: rcu detected stall in __perf_sw_event
run #2: crashed: INFO: rcu detected stall in __perf_sw_event
run #3: crashed: INFO: rcu detected stall in __perf_sw_event
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.20
testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0
run #0: crashed: INFO: rcu detected stall in __perf_sw_event
run #1: crashed: INFO: rcu detected stall in __perf_sw_event
run #2: crashed: INFO: rcu detected stall in __perf_sw_event
run #3: crashed: INFO: rcu detected stall in __perf_sw_event
run #4: crashed: INFO: rcu detected stall in __perf_sw_event
run #5: OK
run #6: OK
run #7: crashed: INFO: rcu detected stall in __perf_sw_event
run #8: OK
run #9: OK
testing release v4.19
testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0
run #0: OK
run #1: crashed: INFO: rcu detected stall in __perf_sw_event
run #2: crashed: INFO: rcu detected stall in __perf_sw_event
run #3: crashed: INFO: rcu detected stall in __perf_sw_event
run #4: crashed: INFO: rcu detected stall in __perf_sw_event
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.18
testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: basic kernel testing failed: timed out
run #4: basic kernel testing failed: timed out
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect start v4.19 v4.18
Bisecting: 7596 revisions left to test after this (roughly 13 steps)
[db06f826ec12bf0701ea7fc0a3c0aa00b84417c8] Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
testing commit db06f826ec12bf0701ea7fc0a3c0aa00b84417c8 with gcc (GCC) 8.1.0
run #0: crashed: INFO: rcu detected stall in __perf_sw_event
run #1: crashed: INFO: rcu detected stall in __perf_sw_event
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad db06f826ec12bf0701ea7fc0a3c0aa00b84417c8
Bisecting: 4493 revisions left to test after this (roughly 12 steps)
[0a957467c5fd46142bc9c52758ffc552d4c5e2f7] x86: i8259: Add missing include file
testing commit 0a957467c5fd46142bc9c52758ffc552d4c5e2f7 with gcc (GCC) 8.1.0
run #0: crashed: INFO: rcu detected stall in __perf_sw_event
run #1: crashed: INFO: rcu detected stall in __perf_sw_event
run #2: crashed: INFO: rcu detected stall in __perf_sw_event
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 0a957467c5fd46142bc9c52758ffc552d4c5e2f7
Bisecting: 1595 revisions left to test after this (roughly 11 steps)
[958f338e96f874a0d29442396d6adf9c1e17aa2d] Merge branch 'l1tf-final' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
testing commit 958f338e96f874a0d29442396d6adf9c1e17aa2d with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: crashed: INFO: rcu detected stall in __perf_sw_event
run #3: crashed: INFO: rcu detected stall in __perf_sw_event
run #4: crashed: INFO: rcu detected stall in __perf_sw_event
run #5: crashed: INFO: rcu detected stall in __perf_sw_event
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 958f338e96f874a0d29442396d6adf9c1e17aa2d
Bisecting: 757 revisions left to test after this (roughly 10 steps)
[85a0b791bc17f7a49280b33e2905d109c062a47b] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
testing commit 85a0b791bc17f7a49280b33e2905d109c062a47b with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: basic kernel testing failed: timed out
run #4: basic kernel testing failed: timed out
run #5: OK
run #6: crashed: INFO: rcu detected stall in __perf_sw_event
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 85a0b791bc17f7a49280b33e2905d109c062a47b
Bisecting: 357 revisions left to test after this (roughly 9 steps)
[8603596a327c978534f5c45db135e6c36b4b1425] Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
testing commit 8603596a327c978534f5c45db135e6c36b4b1425 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: crashed: INFO: rcu detected stall in __perf_sw_event
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 8603596a327c978534f5c45db135e6c36b4b1425
Bisecting: 207 revisions left to test after this (roughly 8 steps)
[2406fb8d94fb17fee3ace0c09427c08825eacb16] Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
testing commit 2406fb8d94fb17fee3ace0c09427c08825eacb16 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: basic kernel testing failed: timed out
run #4: crashed: INFO: rcu detected stall in __perf_sw_event
run #5: crashed: INFO: rcu detected stall in __perf_sw_event
run #6: crashed: INFO: rcu detected stall in __perf_sw_event
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 2406fb8d94fb17fee3ace0c09427c08825eacb16
Bisecting: 96 revisions left to test after this (roughly 7 steps)
[cd23ac8ddb7be993f88bee893b89a8b4971c3651] rcu: Add comment to the last sleep in the rcu tasks loop
testing commit cd23ac8ddb7be993f88bee893b89a8b4971c3651 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect good cd23ac8ddb7be993f88bee893b89a8b4971c3651
Bisecting: 59 revisions left to test after this (roughly 6 steps)
[400439275d9543286f9d3f2925c3156f888e6b18] Merge branch 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
testing commit 400439275d9543286f9d3f2925c3156f888e6b18 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: crashed: INFO: rcu detected stall in __perf_sw_event
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 400439275d9543286f9d3f2925c3156f888e6b18
Bisecting: 18 revisions left to test after this (roughly 4 steps)
[0ad6b38ab2cc00b886c34d945b6a30fdf5108c61] Merge branch 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
testing commit 0ad6b38ab2cc00b886c34d945b6a30fdf5108c61 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: basic kernel testing failed: timed out
run #4: crashed: INFO: rcu detected stall in __perf_sw_event
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 0ad6b38ab2cc00b886c34d945b6a30fdf5108c61
Bisecting: 8 revisions left to test after this (roughly 3 steps)
[ab4d391d2756086e34568f0ff84bc4fc7596e685] m68k/io: Move mem*io define guards to <asm/kmap.h>
testing commit ab4d391d2756086e34568f0ff84bc4fc7596e685 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: basic kernel testing failed: timed out
run #4: crashed: INFO: rcu detected stall in __perf_sw_event
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad ab4d391d2756086e34568f0ff84bc4fc7596e685
Bisecting: 4 revisions left to test after this (roughly 2 steps)
[5b9bfb8ec467b2017f36d7675434822271ce3d29] m68k: mac: Use time64_t in RTC handling
testing commit 5b9bfb8ec467b2017f36d7675434822271ce3d29 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: OK
run #3: crashed: INFO: rcu detected stall in corrupted
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 5b9bfb8ec467b2017f36d7675434822271ce3d29
Bisecting: 1 revision left to test after this (roughly 1 step)
[a8c5cb994341d4af6d75286fcb66684e53295135] nubus: Set default dma mask for nubus_board devices
testing commit a8c5cb994341d4af6d75286fcb66684e53295135 with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: crashed: INFO: rcu detected stall in __perf_sw_event
run #3: crashed: INFO: rcu detected stall in __perf_sw_event
run #4: crashed: INFO: rcu detected stall in corrupted
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad a8c5cb994341d4af6d75286fcb66684e53295135
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[cf85d89562f39cc7ae73de54639f1915a9195b7a] m68k/mac: Enable PDMA for PowerBook 500 series
testing commit cf85d89562f39cc7ae73de54639f1915a9195b7a with gcc (GCC) 8.1.0
run #0: basic kernel testing failed: timed out
run #1: basic kernel testing failed: timed out
run #2: basic kernel testing failed: timed out
run #3: basic kernel testing failed: timed out
run #4: crashed: INFO: rcu detected stall in __perf_sw_event
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad cf85d89562f39cc7ae73de54639f1915a9195b7a
cf85d89562f39cc7ae73de54639f1915a9195b7a is the first bad commit
commit cf85d89562f39cc7ae73de54639f1915a9195b7a
Author: Finn Thain <fthain@telegraphics.com.au>
Date:   Fri May 25 17:34:36 2018 +1000

    m68k/mac: Enable PDMA for PowerBook 500 series
    
    I can confirm that mac_scsi PDMA now works on these machines.
    This increases sequential read throughput by a factor of 4.5.
    
    Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
    Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

:040000 040000 7cecda2f3536bd4c010b1b1daaf0caad055cf125 17c5aa9a815f101c2dcf53fd68bb051f98dd9d82 M	arch
revisions tested: 17, total time: 4h47m54.139933958s (build: 1h40m0.766497691s, test: 3h2m38.0866717s)
first bad commit: cf85d89562f39cc7ae73de54639f1915a9195b7a m68k/mac: Enable PDMA for PowerBook 500 series
cc: ["fthain@telegraphics.com.au" "funaho@jurai.org" "geert@linux-m68k.org" "linux-kernel@vger.kernel.org" "linux-m68k@lists.linux-m68k.org"]
crash: INFO: rcu detected stall in __perf_sw_event
INFO: rcu_preempt self-detected stall on CPU
	1-....: (1 GPs behind) idle=61e/1/4611686018427387906 softirq=23065/23066 fqs=5234 
	 (t=10500 jiffies g=7432 c=7431 q=1448)
NMI backtrace for cpu 1
CPU: 1 PID: 12279 Comm: syz-executor0 Not tainted 4.18.0-rc6+ #1
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+0x109/0x15a lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.5+0x13/0xb1 lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0xf5/0x119 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline]
 rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1336
 print_cpu_stall kernel/rcu/tree.c:1485 [inline]
 check_cpu_stall kernel/rcu/tree.c:1553 [inline]
 __rcu_pending kernel/rcu/tree.c:3244 [inline]
 rcu_pending kernel/rcu/tree.c:3291 [inline]
 rcu_check_callbacks.cold.74+0x4ef/0xda8 kernel/rcu/tree.c:2646
 update_process_times+0x2a/0x60 kernel/time/timer.c:1636
 tick_sched_handle+0x77/0x140 kernel/time/tick-sched.c:164
 tick_sched_timer+0x37/0xf0 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x2e4/0xbd0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x2df/0x760 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
 smp_apic_timer_interrupt+0x10c/0x5c0 arch/x86/kernel/apic/apic.c:1050
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
 </IRQ>
RIP: 0010:__output_copy kernel/events/internal.h:176 [inline]
RIP: 0010:perf_output_read_group kernel/events/core.c:6109 [inline]
RIP: 0010:perf_output_read+0xc7b/0x1470 kernel/events/core.c:6142
Code: c1 ec 03 48 89 85 28 fe ff ff 4b 8d 04 34 49 89 cd 48 89 85 20 fe ff ff 4c 89 cb eb 03 49 89 f5 48 8b 85 28 fe ff ff 80 38 00 <0f> 85 8b 02 00 00 49 8b 4f 18 4d 89 ec 48 8b 85 20 fe ff ff 4c 39 
RSP: 0018:ffff880090ab7188 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffed0012156eb2 RBX: ffff880090ab7330 RCX: 0000000000000010
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff880094504fa0
RBP: ffff880090ab73b8 R08: ffffed00128a0978 R09: ffff880090ab7330
R10: ffffed00128a0977 R11: ffff880094504bbf R12: 1ffff10012156eb4
R13: 0000000000000010 R14: dffffc0000000000 R15: ffff880090ab7578
 perf_output_sample+0xf2b/0x17d0 kernel/events/core.c:6184
 __perf_event_output kernel/events/core.c:6504 [inline]
 perf_event_output_forward+0x10e/0x1f0 kernel/events/core.c:6517
 __perf_event_overflow+0x11f/0x300 kernel/events/core.c:7757
 perf_swevent_overflow+0x62/0xc0 kernel/events/core.c:7833
 perf_swevent_event+0x1f5/0x2f0 kernel/events/core.c:7866
 do_perf_sw_event kernel/events/core.c:7974 [inline]
 ___perf_sw_event+0x25b/0x3f0 kernel/events/core.c:8005
 __perf_sw_event+0x3c/0x60 kernel/events/core.c:8017
 perf_sw_event include/linux/perf_event.h:1054 [inline]
 __do_page_fault+0x59b/0xb20 arch/x86/mm/fault.c:1437
 do_page_fault+0x64/0x43b arch/x86/mm/fault.c:1471
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1160
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x20 arch/x86/lib/copy_user_64.S:181
Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 0f 1f 80 00 00 00 00 0f 1f 00 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 1f 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 83 
RSP: 0018:ffff880090ab7b50 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000020939340 RCX: 0000000000000340
RDX: 0000000000001000 RSI: 000000002093a000 RDI: ffff8800997a9cc0
RBP: ffff880090ab7b78 R08: 0000000000000000 R09: 0000000000000040
R10: ffffed00132f53ff R11: ffff8800997a9fff R12: ffff8800997a9000
R13: ffff8800995b2540 R14: 0000000000001000 R15: ffff880090ab7d78
 copy_page_from_iter_iovec lib/iov_iter.c:290 [inline]
 copy_page_from_iter+0x25c/0x730 lib/iov_iter.c:861
 pipe_write+0x208/0xd10 fs/pipe.c:429
 call_write_iter include/linux/fs.h:1793 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x44e/0x880 fs/read_write.c:487
 vfs_write+0x150/0x4f0 fs/read_write.c:549
 ksys_write+0xcd/0x1b0 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x6e/0xb0 fs/read_write.c:607
 do_syscall_64+0xd6/0x4e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457f89
Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007f1ff713dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457f89
RDX: 0000000041395527 RSI: 0000000020000340 RDI: 0000000000000006
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1ff713e6d4
R13: 00000000004c3cae R14: 00000000004dc448 R15: 00000000ffffffff