bisecting fixing commit since c98875d930e915d01e8c40c7d3c16f00b3c8abe1 building syzkaller on 53199d6e8aee5f0ebd3775d2b1c674f4e6e64e2b testing commit c98875d930e915d01e8c40c7d3c16f00b3c8abe1 with gcc (GCC) 8.1.0 kernel signature: 56211a2169495e4fb95dd8cd9057739543aec837f1bd6cd90afc9ece6300dfe6 all runs: crashed: general protection fault in skb_put testing current HEAD 675cc038067f0e530471c56a7442935f84669d95 testing commit 675cc038067f0e530471c56a7442935f84669d95 with gcc (GCC) 8.1.0 kernel signature: c45a7e7fb23a1a5d03f6bd8b8fdbfee3739154640d246a0b8e1b364cf06a4531 all runs: crashed: general protection fault in skb_put revisions tested: 2, total time: 23m56.198903001s (build: 17m17.524557488s, test: 5m44.316522406s) the crash still happens on HEAD commit msg: Linux 4.19.167 crash: general protection fault in skb_put RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f63577366d4 R13: 00000000004c3102 R14: 00000000004d64a8 R15: 0000000000000004 Bluetooth: Can't allocate mem for new packet kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 23 Comm: kworker/u4:1 Not tainted 4.19.167-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:1697 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:ffff8881f503fa88 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881db53cddc RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8881f503fab0 R08: ffffed103ed24733 R09: ffffed103ed24732 R10: ffffed103ed24732 R11: ffff8881f6923993 R12: ffff8881da01202a R13: 00000000000000c8 R14: ffff8881db53cc80 R15: ffff8881db53cd78 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000073c061 CR3: 000000000806d004 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_put_data include/linux/skbuff.h:2123 [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 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:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x34a/0x410 kernel/kthread.c:259 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415 Modules linked in: ---[ end trace 9abdca2507eddccf ]--- RIP: 0010:skb_put+0x28/0x1e0 net/core/skbuff.c:1697 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:ffff8881f503fa88 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881db53cddc RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8881f503fab0 R08: ffffed103ed24733 R09: ffffed103ed24732 R10: ffffed103ed24732 R11: ffff8881f6923993 R12: ffff8881da01202a R13: 00000000000000c8 R14: ffff8881db53cc80 R15: ffff8881db53cd78 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005598c1b7f990 CR3: 000000000806d004 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400