bisecting fixing commit since ab2d1d40a128f4b8f8857ae3ecd312c79b3ff8a1 building syzkaller on 6bdac76629d4d80501671c0c312d6b81411481e7 testing commit ab2d1d40a128f4b8f8857ae3ecd312c79b3ff8a1 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: f8efc57100d4d227f4be4a928d42fffabbaabdf4963a640064c138f611cc2ca9 run #0: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #1: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #2: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #3: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #4: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #5: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #6: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #7: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #8: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #9: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #10: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #11: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #12: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #13: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #14: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #15: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #16: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #17: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #18: OK run #19: OK testing current HEAD 73c2a811f6d17d60e03a0cb5c0fa17fab7e982e2 testing commit 73c2a811f6d17d60e03a0cb5c0fa17fab7e982e2 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: a64cc4ee7b5174f55dce974fc34ce4285ec8f36b39d29069ef3674179de79826 run #0: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #1: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #2: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #3: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #4: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #5: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #6: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #7: crashed: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return run #8: OK run #9: OK revisions tested: 2, total time: 25m28.086075249s (build: 7m53.713173477s, test: 17m2.891860433s) the crash still happens on HEAD commit msg: Revert "xfrm: Add possibility to set the default to block if we have no policy" crash: BUG: using smp_processor_id() in preemptible code in usbnet_skb_return BUG: using smp_processor_id() in preemptible [00000000] code: dhcpcd/209 caller is debug_smp_processor_id+0x17/0x20 lib/smp_processor_id.c:59 CPU: 1 PID: 209 Comm: dhcpcd Not tainted 5.10.118-syzkaller #0 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_lvl+0x81/0xac lib/dump_stack.c:118 dump_stack+0x10/0x12 lib/dump_stack.c:135 check_preemption_disabled+0xc4/0xd0 lib/smp_processor_id.c:48 debug_smp_processor_id+0x17/0x20 lib/smp_processor_id.c:59 usbnet_skb_return+0x43/0x290 drivers/net/usb/usbnet.c:307 usbnet_resume_rx+0x34/0x80 drivers/net/usb/usbnet.c:680 usbnet_change_mtu+0x1d5/0x2a0 drivers/net/usb/usbnet.c:393 __dev_set_mtu net/core/dev.c:8578 [inline] dev_set_mtu_ext+0x28d/0x5d0 net/core/dev.c:8631 dev_set_mtu+0x97/0x100 net/core/dev.c:8655 dev_ifsioc+0x441/0x750 net/core/dev_ioctl.c:261 dev_ioctl+0x146/0x910 net/core/dev_ioctl.c:505 sock_do_ioctl+0x172/0x240 net/socket.c:1071 sock_ioctl+0x336/0x600 net/socket.c:1188 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x129/0x1a0 fs/ioctl.c:739 do_syscall_64+0x32/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5eb3e9b0e7 Code: 3c 1c e8 1c ff ff ff 85 c0 79 87 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 61 9d 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc2122e818 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5eb3dad6c8 RCX: 00007f5eb3e9b0e7 RDX: 00007ffc2123ea08 RSI: 0000000000008922 RDI: 0000000000000012 RBP: 00007ffc2124ebb8 R08: 00007ffc2123e9c8 R09: 00007ffc2123e978 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc2123ea08 R14: 0000000000000028 R15: 0000000000008922