bisecting fixing commit since cbfa1702aaf69b2311ea1b35e04f113c48368c67 building syzkaller on 062c9832a6cdb39bf38ad7a6dad51300a2e9a734 testing commit cbfa1702aaf69b2311ea1b35e04f113c48368c67 with gcc (GCC) 8.4.1 20210217 kernel signature: 9907eec2b6b9da90f6e23c347d9b3c8821aad03f8b075764ec6dcbe5f64bb644 run #0: crashed: KASAN: use-after-free Read in perf_output_read run #1: crashed: KASAN: slab-out-of-bounds Read in perf_output_read run #2: crashed: KASAN: use-after-free Read in perf_output_read run #3: crashed: KASAN: use-after-free Read in perf_output_read run #4: crashed: KASAN: use-after-free Read in perf_output_read run #5: crashed: KASAN: use-after-free Read in perf_output_read run #6: crashed: KASAN: use-after-free Read in perf_output_read run #7: crashed: KASAN: use-after-free Read in perf_output_read run #8: crashed: KASAN: use-after-free Read in perf_output_read run #9: crashed: KASAN: use-after-free Read in perf_output_read run #10: crashed: KASAN: use-after-free Read in perf_output_read run #11: crashed: KASAN: use-after-free Read in perf_output_read run #12: crashed: KASAN: use-after-free Read in perf_output_read run #13: crashed: KASAN: use-after-free Read in perf_output_read run #14: crashed: KASAN: use-after-free Read in perf_output_read run #15: crashed: KASAN: use-after-free Read in perf_output_read run #16: crashed: KASAN: use-after-free Read in perf_output_read run #17: crashed: KASAN: use-after-free Read in perf_output_read run #18: OK run #19: OK testing current HEAD cb83ddcd5332fcc3efd52ba994976efc4dd6061e testing commit cb83ddcd5332fcc3efd52ba994976efc4dd6061e with gcc (GCC) 8.4.1 20210217 kernel signature: 997e313a9268c9f8a7053b90577a1fd0c6cef16bfb3522ba18a1843eb5d3eb72 run #0: crashed: KASAN: use-after-free Read in perf_output_read run #1: crashed: KASAN: use-after-free Read in perf_output_read run #2: crashed: KASAN: use-after-free Read in perf_output_read run #3: crashed: KASAN: use-after-free Read in perf_output_read run #4: crashed: KASAN: slab-out-of-bounds Read in perf_output_read run #5: crashed: KASAN: use-after-free Read in perf_output_read run #6: crashed: KASAN: slab-out-of-bounds Read in perf_output_read run #7: crashed: KASAN: use-after-free Read in perf_output_read run #8: crashed: KASAN: use-after-free Read in perf_output_read run #9: crashed: BUG: soft lockup in __perf_sw_event revisions tested: 2, total time: 36m34.053916861s (build: 14m59.988166953s, test: 21m11.648544195s) the crash still happens on HEAD commit msg: Linux 4.14.226 crash: BUG: soft lockup in __perf_sw_event IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready batman_adv: batadv0: Interface activated: batadv_slave_1 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor108:24684] Modules linked in: irq event stamp: 18024 hardirqs last enabled at (18023): [] restore_regs_and_return_to_kernel+0x0/0x23 hardirqs last disabled at (18024): [] apic_timer_interrupt+0x95/0xa0 arch/x86/entry/entry_64.S:793 softirqs last enabled at (12930): [] __do_softirq+0x644/0x9a2 kernel/softirq.c:314 softirqs last disabled at (12899): [] invoke_softirq kernel/softirq.c:368 [inline] softirqs last disabled at (12899): [] irq_exit+0x15f/0x1a0 kernel/softirq.c:409 CPU: 0 PID: 24684 Comm: syz-executor108 Not tainted 4.14.226-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881e29b2580 task.stack: ffff8881c5d08000 RIP: 0010:perf_output_read_group kernel/events/core.c:5895 [inline] RIP: 0010:perf_output_read+0x59f/0x14f0 kernel/events/core.c:5930 RSP: 0018:ffff8881c5d0f010 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10 RAX: 1ffff1103c30eabf RBX: 0000000000000000 RCX: 0000000000000001 RDX: 1ffff1103c30eafa RSI: 0000000000000000 RDI: ffff8881e18757d0 RBP: ffff8881c5d0f160 R08: ffff88823fff8018 R09: 0000000000000008 R10: ffffed1047fff001 R11: 0000006f5c6b292b R12: ffff8881c5d0f320 R13: ffff8881e1875340 R14: ffff8881c5d0f138 R15: dffffc0000000000 FS: 00007f5cea023700(0000) GS:ffff8881f6600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000800000001 CR3: 00000001d3be2002 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: perf_output_sample+0x1276/0x1910 kernel/events/core.c:5972 __perf_event_output kernel/events/core.c:6285 [inline] perf_event_output_forward+0x103/0x1d0 kernel/events/core.c:6298 __perf_event_overflow+0x107/0x300 kernel/events/core.c:7547 perf_swevent_overflow+0x165/0x210 kernel/events/core.c:7623 perf_swevent_event+0x1f5/0x2f0 kernel/events/core.c:7656 do_perf_sw_event kernel/events/core.c:7764 [inline] ___perf_sw_event+0x26b/0x3f0 kernel/events/core.c:7795 __perf_sw_event+0x3c/0x60 kernel/events/core.c:7807 perf_sw_event include/linux/perf_event.h:1046 [inline] __do_page_fault+0x648/0xb10 arch/x86/mm/fault.c:1483 do_page_fault+0x64/0x400 arch/x86/mm/fault.c:1517 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1123 RIP: 0010:copy_user_enhanced_fast_string+0xe/0x20 arch/x86/lib/copy_user_64.S:181 RSP: 0018:ffff8881c5d0f918 EFLAGS: 00010206 RAX: 0000000000000000 RBX: 0000000020efdacb RCX: 0000000000001053 RDX: 0000000000004588 RSI: 0000000020f01000 RDI: ffff8881de87b535 RBP: ffff8881c5d0f940 R08: ffffed103bd0f8b1 R09: ffffed103bd0f8b1 R10: ffffed103bd0f8b0 R11: ffff8881de87c587 R12: ffff8881de878000 R13: ffff8881e29b2580 R14: ffff8881c5d0fdb0 R15: ffff8881c5d0fd60 _copy_from_iter_full+0x166/0x760 lib/iov_iter.c:608 copy_from_iter_full include/linux/uio.h:126 [inline] skb_do_copy_data_nocache include/net/sock.h:1889 [inline] skb_copy_to_page_nocache include/net/sock.h:1915 [inline] tcp_sendmsg_locked+0x193f/0x3a10 net/ipv4/tcp.c:1360 tcp_sendmsg+0x27/0x40 net/ipv4/tcp.c:1457 inet_sendmsg+0x108/0x440 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:656 SYSC_sendto net/socket.c:1763 [inline] SyS_sendto+0x1e4/0x2c0 net/socket.c:1731 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x449179 RSP: 002b:00007f5cea023308 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00000000004ce4e8 RCX: 0000000000449179 RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000004 RBP: 00000000004ce4e0 R08: 0000000000000000 R09: 0000000000000053 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049d474 R13: 00007ffef17b4adf R14: 00007f5cea023400 R15: 0000000000022000 Code: 89 f8 48 c1 e8 03 42 80 3c 38 00 0f 85 f7 0b 00 00 49 8d bd 90 04 00 00 49 8b 9d b8 02 00 00 48 89 fa 48 c1 ea 03 42 80 3c 3a 00 <0f> 85 cd 0b 00 00 48 85 db 49 8b 95 90 04 00 00 74 20 48 8d bb