bisecting fixing commit since c98875d930e915d01e8c40c7d3c16f00b3c8abe1 building syzkaller on 53199d6e8aee5f0ebd3775d2b1c674f4e6e64e2b testing commit c98875d930e915d01e8c40c7d3c16f00b3c8abe1 with gcc (GCC) 8.4.1 20210217 kernel signature: 2384b2413b3e30009dac5642db10b433f0d691ed362df34bf90adec2c3731eaf run #0: crashed: general protection fault in skb_put run #1: crashed: general protection fault in skb_put run #2: crashed: general protection fault in corrupted run #3: crashed: general protection fault in skb_put run #4: crashed: general protection fault in skb_put run #5: crashed: general protection fault in skb_put run #6: crashed: general protection fault in skb_put run #7: crashed: general protection fault in skb_put run #8: crashed: general protection fault in skb_put run #9: crashed: general protection fault in skb_put run #10: crashed: general protection fault in skb_put run #11: crashed: general protection fault in skb_put run #12: crashed: general protection fault in skb_put run #13: crashed: general protection fault in skb_put run #14: crashed: general protection fault in skb_put run #15: crashed: general protection fault in skb_put run #16: crashed: general protection fault in corrupted run #17: crashed: general protection fault in skb_put run #18: crashed: general protection fault in skb_put run #19: boot failed: can't ssh into the instance testing current HEAD 2965db2e004cf9c92b87c1f559e9812c0ae878c1 testing commit 2965db2e004cf9c92b87c1f559e9812c0ae878c1 with gcc (GCC) 8.4.1 20210217 kernel signature: 7aa6bf0653323e5ebd49f090c536c2ea59bbb9279af5c82351a2a2e09e436052 all runs: crashed: general protection fault in skb_put revisions tested: 2, total time: 28m26.978078958s (build: 14m19.775688352s, test: 13m28.947211772s) the crash still happens on HEAD commit msg: Linux 4.19.188 crash: general protection fault in skb_put hci_uart_tty_receive+0x1d4/0x470 drivers/bluetooth/hci_ldisc.c:621 tiocsti drivers/tty/tty_io.c:2194 [inline] tty_ioctl+0x64e/0x12a0 drivers/tty/tty_io.c:2580 general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3452 Comm: kworker/u4:5 Not tainted 4.19.188-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x199/0x10d0 fs/ioctl.c:688 Workqueue: events_unbound flush_to_ldisc RIP: 0010:skb_put+0x28/0x1e0 net/core/skbuff.c:1706 Code: 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 55 4c 8d af c8 00 00 00 41 54 4c 89 ea 53 48 89 fb 48 c1 ea 03 48 83 ec 10 <0f> b6 14 02 4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 28 RSP: 0018:ffff8881d3227a88 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881e0884b5c RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8881d3227ab0 R08: ffffed103ed04733 R09: ffffed103ed04732 R10: ffffed103ed04732 R11: ffff8881f6823993 R12: ffff8881e1355b6a R13: 00000000000000c8 R14: ffff8881e0884a00 R15: ffff8881e0884af8 FS: 0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8b2cff8000 CR3: 000000000806d001 CR4: 00000000001606f0 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 do_syscall_64+0xd6/0x4e0 arch/x86/entry/common.c:293 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 entry_SYSCALL_64_after_hwframe+0x49/0xbe Call Trace: RIP: 0033:0x4603b9 skb_put_data include/linux/skbuff.h:2128 [inline] bcsp_unslip_one_byte drivers/bluetooth/hci_bcsp.c:451 [inline] bcsp_recv+0x9bb/0x1650 drivers/bluetooth/hci_bcsp.c:613 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f13a7f22198 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000052bf00 RCX: 00000000004603b9 RDX: 0000000020000100 RSI: 0000000000005412 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 hci_uart_tty_receive+0x1d4/0x470 drivers/bluetooth/hci_ldisc.c:621 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 tty_ldisc_receive_buf+0x103/0x1c0 drivers/tty/tty_buffer.c:460 R13: 0000000000000003 R14: 00000000004ae997 R15: 00007f13a7f226bc tty_port_default_receive_buf+0x5f/0x90 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:476 [inline] flush_to_ldisc+0x1af/0x3a0 drivers/tty/tty_buffer.c:528 process_one_work+0x835/0x1670 kernel/workqueue.c:2152 worker_thread+0x85/0xb60 kernel/workqueue.c:2295 kthread+0x34a/0x410 kernel/kthread.c:259 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415 Modules linked in: Bluetooth: Can't allocate mem for new packet kasan: GPF could be caused by NULL-ptr deref or user memory access Bluetooth: Can't allocate mem for new packet general protection fault: 0000 [#2] PREEMPT SMP KASAN CPU: 1 PID: 2432 Comm: kworker/u4:4 Tainted: G D 4.19.188-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc RIP: 0010:skb_put+0x28/0x1e0 net/core/skbuff.c:1706 Code: 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 55 4c 8d af c8 00 00 00 41 54 4c 89 ea 53 48 89 fb 48 c1 ea 03 48 83 ec 10 <0f> b6 14 02 4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 28 RSP: 0018:ffff8881ea66fa88 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881e5f87ddc RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8881ea66fab0 R08: ffffed103ed04733 R09: ffffed103ed04732 R10: ffffed103ed04732 R11: ffff8881f6823993 R12: ffff8881e0a52dea R13: 00000000000000c8 R14: ffff8881e5f87c80 R15: ffff8881e5f87d78 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055ca02b02078 CR3: 000000000806d006 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 ---[ end trace 883c697c9446c30b ]--- DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_put_data include/linux/skbuff.h:2128 [inline] bcsp_unslip_one_byte drivers/bluetooth/hci_bcsp.c:451 [inline] bcsp_recv+0x9bb/0x1650 drivers/bluetooth/hci_bcsp.c:613 hci_uart_tty_receive+0x1d4/0x470 drivers/bluetooth/hci_ldisc.c:621 tty_ldisc_receive_buf+0x103/0x1c0 drivers/tty/tty_buffer.c:460 tty_port_default_receive_buf+0x5f/0x90 drivers/tty/tty_port.c:38 RIP: 0010:skb_put+0x28/0x1e0 net/core/skbuff.c:1706 receive_buf drivers/tty/tty_buffer.c:476 [inline] flush_to_ldisc+0x1af/0x3a0 drivers/tty/tty_buffer.c:528 process_one_work+0x835/0x1670 kernel/workqueue.c:2152 worker_thread+0x85/0xb60 kernel/workqueue.c:2295 kthread+0x34a/0x410 kernel/kthread.c:259 Code: 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 55 4c 8d af c8 00 00 00 41 54 4c 89 ea 53 48 89 fb 48 c1 ea 03 48 83 ec 10 <0f> b6 14 02 4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 28 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415 Modules linked in: RSP: 0018:ffff8881d3227a88 EFLAGS: 00010286 ---[ end trace 883c697c9446c30c ]--- RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881e0884b5c RIP: 0010:skb_put+0x28/0x1e0 net/core/skbuff.c:1706 RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 Code: 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 55 4c 8d af c8 00 00 00 41 54 4c 89 ea 53 48 89 fb 48 c1 ea 03 48 83 ec 10 <0f> b6 14 02 4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 28 RBP: ffff8881d3227ab0 R08: ffffed103ed04733 R09: ffffed103ed04732 RSP: 0018:ffff8881d3227a88 EFLAGS: 00010286 R10: ffffed103ed04732 R11: ffff8881f6823993 R12: ffff8881e1355b6a RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881e0884b5c R13: 00000000000000c8 R14: ffff8881e0884a00 R15: ffff8881e0884af8 RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 RBP: ffff8881d3227ab0 R08: ffffed103ed04733 R09: ffffed103ed04732 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 R10: ffffed103ed04732 R11: ffff8881f6823993 R12: ffff8881e1355b6a CR2: 00007fb115854740 CR3: 000000000806d003 CR4: 00000000001606f0 R13: 00000000000000c8 R14: ffff8881e0884a00 R15: ffff8881e0884af8 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033