bisecting fixing commit since c98875d930e915d01e8c40c7d3c16f00b3c8abe1 building syzkaller on 53199d6e8aee5f0ebd3775d2b1c674f4e6e64e2b testing commit c98875d930e915d01e8c40c7d3c16f00b3c8abe1 with gcc (GCC) 8.1.0 kernel signature: 56211a2169495e4fb95dd8cd9057739543aec837f1bd6cd90afc9ece6300dfe6 run #0: crashed: KASAN: use-after-free Read in bcsp_recv run #1: crashed: general protection fault in skb_put run #2: crashed: general protection fault in skb_put 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 corrupted 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 bcsp_recv testing current HEAD 13d2ce42de8cb98ff952f8de6307f896203854c2 testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 with gcc (GCC) 8.1.0 kernel signature: 831d1d0616dcd8a33e4636d75bcaf12ff1db6e1cba46787a272e6299bad32ec0 all runs: crashed: general protection fault in skb_put revisions tested: 2, total time: 24m15.28563615s (build: 17m35.520786583s, test: 5m41.168502258s) the crash still happens on HEAD commit msg: Linux 4.19.163 crash: general protection fault in skb_put RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f580d57e6d4 R13: 00000000004c3102 R14: 00000000004d64a8 R15: 0000000000000004 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN Bluetooth: Can't allocate mem for new packet CPU: 0 PID: 30 Comm: kworker/u4:2 Not tainted 4.19.163-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:ffff8881f513fa88 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881dd45821c RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8881f513fab0 R08: ffffed103ed04733 R09: ffffed103ed04732 R10: ffffed103ed04732 R11: ffff8881f6823993 R12: ffff8881e8896dea R13: 00000000000000c8 R14: ffff8881dd4580c0 R15: ffff8881dd4581b8 FS: 0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f662ea264a0 CR3: 000000000806d002 CR4: 00000000001606f0 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 3d6f9822fe603298 ]--- 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:ffff8881f513fa88 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8881dd45821c RDX: 0000000000000019 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8881f513fab0 R08: ffffed103ed04733 R09: ffffed103ed04732 R10: ffffed103ed04732 R11: ffff8881f6823993 R12: ffff8881e8896dea R13: 00000000000000c8 R14: ffff8881dd4580c0 R15: ffff8881dd4581b8 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 FS: 0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CPU: 0 PID: 6655 Comm: syz-executor.4 Tainted: G D 4.19.163-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+0x123/0x177 lib/dump_stack.c:118 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0x5/0x13 lib/fault-inject.c:149 __should_failslab+0xba/0xf0 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1588 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc_node mm/slab.c:3304 [inline] kmem_cache_alloc_node+0x56/0x730 mm/slab.c:3647 __alloc_skb+0xa7/0x580 net/core/skbuff.c:193 alloc_skb include/linux/skbuff.h:995 [inline] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [inline] bcsp_recv+0x21f/0x1650 drivers/bluetooth/hci_bcsp.c:688 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 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x199/0x10d0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __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 do_syscall_64+0xd6/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458ca9 Code: 2d b8 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 fb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fa1dd0e1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa1dd0e1c90 RCX: 0000000000458ca9 RDX: 0000000020000100 RSI: 0000000000005412 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa1dd0e26d4 R13: 00000000004c3102 R14: 00000000004d64a8 R15: 0000000000000004 CPU: 1 PID: 6657 Comm: syz-executor.1 Tainted: G D 4.19.163-syzkaller #0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 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+0x123/0x177 lib/dump_stack.c:118 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0x5/0x13 lib/fault-inject.c:149 __should_failslab+0xba/0xf0 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1588 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc_node mm/slab.c:3304 [inline] kmem_cache_alloc_node+0x56/0x730 mm/slab.c:3647 __alloc_skb+0xa7/0x580 net/core/skbuff.c:193 CR2: 00005623d4e906d8 CR3: 000000000806d006 CR4: 00000000001606f0 alloc_skb include/linux/skbuff.h:995 [inline] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [inline] bcsp_recv+0x21f/0x1650 drivers/bluetooth/hci_bcsp.c:688 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 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 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x199/0x10d0 fs/ioctl.c:688