bisecting cause commit starting from 091a1eaa0e309b0e8dcbf3f2da12c7f3d03ed182 building syzkaller on 8b311eafa7f32ebcae67cdf5e16aa1ab3fc77e7f testing commit 091a1eaa0e309b0e8dcbf3f2da12c7f3d03ed182 with gcc (GCC) 8.1.0 run #0: crashed: WARNING in port_delete run #1: crashed: WARNING in port_delete run #2: crashed: WARNING in port_delete run #3: crashed: WARNING in port_delete run #4: crashed: WARNING in port_delete 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 all runs: OK # git bisect start 091a1eaa0e309b0e8dcbf3f2da12c7f3d03ed182 v4.18 Bisecting: 7402 revisions left to test after this (roughly 13 steps) [71f3a82fab1b631ae9cb1feb677f498d4ca5007d] Merge tag 'media/v4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media testing commit 71f3a82fab1b631ae9cb1feb677f498d4ca5007d with gcc (GCC) 8.1.0 run #0: crashed: WARNING in port_delete run #1: OK 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 71f3a82fab1b631ae9cb1feb677f498d4ca5007d Bisecting: 4288 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: WARNING in port_delete run #1: OK 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 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: crashed: WARNING in port_delete run #1: OK 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 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: crashed: WARNING in port_delete run #1: crashed: WARNING in port_delete 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 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: crashed: WARNING in port_delete run #1: crashed: WARNING in port_delete 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 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: crashed: WARNING in port_delete run #1: crashed: WARNING in port_delete 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 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: crashed: WARNING in port_delete run #1: crashed: WARNING in port_delete run #2: crashed: WARNING in port_delete run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK # git bisect bad cd23ac8ddb7be993f88bee893b89a8b4971c3651 Bisecting: 47 revisions left to test after this (roughly 6 steps) [e1333462e3cf933ab860c693ef1ff50775c7ea7f] doc: Update RCU CPU stall-warning documentation testing commit e1333462e3cf933ab860c693ef1ff50775c7ea7f with gcc (GCC) 8.1.0 run #0: crashed: WARNING in port_delete run #1: crashed: WARNING in port_delete run #2: crashed: WARNING in port_delete run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK # git bisect bad e1333462e3cf933ab860c693ef1ff50775c7ea7f Bisecting: 23 revisions left to test after this (roughly 5 steps) [67e14c1e39d2d956300b3d6ad00f7708e3285531] rcu: Move RCU's grace-period-change code to ->gp_seq testing commit 67e14c1e39d2d956300b3d6ad00f7708e3285531 with gcc (GCC) 8.1.0 all runs: OK # git bisect good 67e14c1e39d2d956300b3d6ad00f7708e3285531 Bisecting: 11 revisions left to test after this (roughly 4 steps) [ab5e869c1f7aa30a1210f5e8a277758b0599609f] rcu: Make rcu_nocb_wait_gp() check if GP already requested testing commit ab5e869c1f7aa30a1210f5e8a277758b0599609f with gcc (GCC) 8.1.0 all runs: OK # git bisect good ab5e869c1f7aa30a1210f5e8a277758b0599609f Bisecting: 5 revisions left to test after this (roughly 3 steps) [db023296f0115d2fe01fdabad54678f2b806da23] rcu: Convert rcu_quiescent_state_report tracepoint to ->gp_seq testing commit db023296f0115d2fe01fdabad54678f2b806da23 with gcc (GCC) 8.1.0 run #0: crashed: WARNING in port_delete run #1: crashed: WARNING in port_delete 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 db023296f0115d2fe01fdabad54678f2b806da23 Bisecting: 2 revisions left to test after this (roughly 2 steps) [63d86a7e85f84b8ac3b2f394570965aedbb03787] rcu: Convert rcu_grace_period_init tracepoint to gp_seq testing commit 63d86a7e85f84b8ac3b2f394570965aedbb03787 with gcc (GCC) 8.1.0 run #0: crashed: WARNING in port_delete run #1: OK 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 63d86a7e85f84b8ac3b2f394570965aedbb03787 Bisecting: 0 revisions left to test after this (roughly 1 step) [abd13fdd9516e5baae2257721b921684ecb090d3] rcu: Convert rcu_future_grace_period tracepoint to gp_seq testing commit abd13fdd9516e5baae2257721b921684ecb090d3 with gcc (GCC) 8.1.0 all runs: OK # git bisect good abd13fdd9516e5baae2257721b921684ecb090d3 63d86a7e85f84b8ac3b2f394570965aedbb03787 is the first bad commit commit 63d86a7e85f84b8ac3b2f394570965aedbb03787 Author: Paul E. McKenney Date: Tue May 1 13:08:46 2018 -0700 rcu: Convert rcu_grace_period_init tracepoint to gp_seq This commit makes the rcu_grace_period_init tracepoint use gp_seq instead of ->gpnum. Signed-off-by: Paul E. McKenney :040000 040000 9e12d879cf3038219131a331600c29880a5c8806 650abce82c24a0a5fb6745ca5d0a90366a9505c1 M include revisions tested: 15, total time: 4h33m14.794762278s (build: 1h42m18.479614013s, test: 2h43m47.159227768s) first bad commit: 63d86a7e85f84b8ac3b2f394570965aedbb03787 rcu: Convert rcu_grace_period_init tracepoint to gp_seq cc: ["linux-kernel@vger.kernel.org" "mingo@redhat.com" "paulmck@linux.vnet.ibm.com" "rostedt@goodmis.org"] crash: WARNING in port_delete WARNING: CPU: 1 PID: 19332 at sound/core/seq/seq_ports.c:275 port_delete+0x13c/0x170 sound/core/seq/seq_ports.c:276 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 19332 Comm: syz-executor1 Not tainted 4.18.0-rc1+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x16e/0x22a lib/dump_stack.c:113 panic+0x1c6/0x37d kernel/panic.c:184 __warn.cold.8+0x120/0x16c kernel/panic.c:536 report_bug+0x1a4/0x200 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 RIP: 0010:port_delete+0x13c/0x170 sound/core/seq/seq_ports.c:275 Code: 03 0f b6 04 02 84 c0 74 04 3c 03 7e 21 8b 83 58 01 00 00 85 c0 75 0f 48 89 df e8 5f 33 15 fc 31 c0 5b 41 5c 5d c3 0f 0b eb ed <0f> 0b eb bb e8 5b 5f 15 fc eb d8 e8 54 5f 15 fc eb a6 e8 ad 5f 15 RSP: 0018:ffff8801b9707898 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8801cede0940 RCX: 1ffff100378b79d3 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8801cede09b8 RBP: ffff8801b97078a8 R08: ffff8801bc5bce98 R09: 0000000000000006 R10: 0000000000000000 R11: ffff8801bc5bc600 R12: ffffffff859d4010 R13: 1ffff100372e0f1d R14: ffff8801cede0940 R15: ffff8801cb005810 snd_seq_delete_port+0x33c/0x5e0 sound/core/seq/seq_ports.c:303 snd_seq_ioctl_delete_port+0xa0/0x170 sound/core/seq/seq_clientmgr.c:1325 snd_seq_kernel_client_ctl+0xe3/0x150 sound/core/seq/seq_clientmgr.c:2360 snd_seq_event_port_detach+0xf1/0x160 sound/core/seq/seq_ports.c:705 delete_port+0x66/0xa0 sound/core/seq/oss/seq_oss_init.c:354 snd_seq_oss_release+0xda/0x110 sound/core/seq/oss/seq_oss_init.c:433 odev_release+0x49/0x70 sound/core/seq/oss/seq_oss.c:153 __fput+0x2ec/0x990 fs/file_table.c:209 ____fput+0x9/0x10 fs/file_table.c:243 task_work_run+0x19f/0x240 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:192 [inline] exit_to_usermode_loop+0x267/0x300 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x587/0x700 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4576c9 Code: 1d b4 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fcfe0639c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000004576c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcfe063a6d4 R13: 00000000004ef9b2 R14: 00000000004cc500 R15: 00000000ffffffff Kernel Offset: disabled Rebooting in 86400 seconds..