bisecting cause commit starting from 4608a726c66807c27bc7d91bdf8a288254e29985
building syzkaller on f62e1e85cf54ccfa990868a402eca32bf4513b21
testing commit 4608a726c66807c27bc7d91bdf8a288254e29985 with gcc (GCC) 8.1.0
run #0: crashed: KASAN: use-after-free Read in nr_insert_socket
run #1: crashed: KASAN: use-after-free Read in nr_insert_socket
run #2: crashed: WARNING: refcount bug in nr_insert_socket
run #3: crashed: WARNING: refcount bug in nr_insert_socket
run #4: crashed: WARNING: refcount bug in nr_insert_socket
run #5: crashed: general protection fault in send_hsr_supervision_frame
run #6: crashed: general protection fault in send_hsr_supervision_frame
run #7: crashed: KASAN: use-after-free Read in nr_insert_socket
run #8: crashed: KASAN: use-after-free Read in nr_insert_socket
run #9: OK
testing release v5.2
testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0
all runs: OK
# git bisect start 4608a726c66807c27bc7d91bdf8a288254e29985 v5.2
Bisecting: 6261 revisions left to test after this (roughly 13 steps)
[05bdbf55cec10eedec3cc3a446cc6032df83e371] Merge remote-tracking branch 'net-next/master'
testing commit 05bdbf55cec10eedec3cc3a446cc6032df83e371 with gcc (GCC) 8.1.0
run #0: crashed: KASAN: use-after-free Read in nr_release
run #1: crashed: KASAN: use-after-free Read in lock_sock_nested
run #2: crashed: WARNING: refcount bug in nr_insert_socket
run #3: crashed: KASAN: use-after-free Read in nr_insert_socket
run #4: crashed: WARNING: refcount bug in nr_insert_socket
run #5: crashed: KASAN: use-after-free Read in lock_sock_nested
run #6: crashed: KASAN: use-after-free Read in nr_release
run #7: crashed: general protection fault in send_hsr_supervision_frame
run #8: crashed: general protection fault in send_hsr_supervision_frame
run #9: OK
# git bisect bad 05bdbf55cec10eedec3cc3a446cc6032df83e371
Bisecting: 3655 revisions left to test after this (roughly 12 steps)
[5a535b2eeae86a0daa298705ff14de187c18589d] Merge remote-tracking branch 'v9fs/9p-next'
testing commit 5a535b2eeae86a0daa298705ff14de187c18589d with gcc (GCC) 8.1.0
run #0: crashed: KASAN: use-after-free Read in nr_insert_socket
run #1: crashed: WARNING: refcount bug in nr_insert_socket
run #2: crashed: KASAN: use-after-free Read in nr_insert_socket
run #3: crashed: KASAN: use-after-free Read in nr_insert_socket
run #4: crashed: WARNING: refcount bug in nr_insert_socket
run #5: crashed: KASAN: use-after-free Read in lock_sock_nested
run #6: crashed: general protection fault in send_hsr_supervision_frame
run #7: crashed: general protection fault in send_hsr_supervision_frame
run #8: OK
run #9: OK
# git bisect bad 5a535b2eeae86a0daa298705ff14de187c18589d
Bisecting: 2014 revisions left to test after this (roughly 11 steps)
[f67a5352c5584c3bf796267caebc0885d1c7607d] Merge remote-tracking branch 'arm/for-next'
testing commit f67a5352c5584c3bf796267caebc0885d1c7607d with gcc (GCC) 8.1.0
run #0: crashed: WARNING: refcount bug in nr_insert_socket
run #1: crashed: KASAN: use-after-free Read in lock_sock_nested
run #2: crashed: WARNING: refcount bug in nr_insert_socket
run #3: crashed: WARNING: refcount bug in nr_insert_socket
run #4: crashed: WARNING: refcount bug in nr_insert_socket
run #5: crashed: general protection fault in send_hsr_supervision_frame
run #6: crashed: general protection fault in send_hsr_supervision_frame
run #7: OK
run #8: OK
run #9: OK
# git bisect bad f67a5352c5584c3bf796267caebc0885d1c7607d
Bisecting: 917 revisions left to test after this (roughly 10 steps)
[0dcb4efb1095d0a1f5f681c2b94e98b009cc5d77] ALSA: firewire-lib: code refactoring for local variables
testing commit 0dcb4efb1095d0a1f5f681c2b94e98b009cc5d77 with gcc (GCC) 8.1.0
all runs: OK
# git bisect good 0dcb4efb1095d0a1f5f681c2b94e98b009cc5d77
Bisecting: 496 revisions left to test after this (roughly 9 steps)
[a3e95c1fa1631fb00a0d429c430c1f28b9fc864e] Merge remote-tracking branch 'sparc/master'
testing commit a3e95c1fa1631fb00a0d429c430c1f28b9fc864e with gcc (GCC) 8.1.0
all runs: OK
# git bisect good a3e95c1fa1631fb00a0d429c430c1f28b9fc864e
Bisecting: 199 revisions left to test after this (roughly 8 steps)
[946c8eb20f5fce2069a12ef8fe414c0c21acac1d] Merge remote-tracking branch 'crypto-current/master'
testing commit 946c8eb20f5fce2069a12ef8fe414c0c21acac1d with gcc (GCC) 8.1.0
run #0: crashed: WARNING: refcount bug in nr_insert_socket
run #1: crashed: WARNING: refcount bug in nr_insert_socket
run #2: crashed: KASAN: use-after-free Read in nr_release
run #3: crashed: KASAN: use-after-free Read in lock_sock_nested
run #4: crashed: KASAN: use-after-free Read in nr_insert_socket
run #5: crashed: general protection fault in send_hsr_supervision_frame
run #6: crashed: KASAN: use-after-free Read in lock_sock_nested
run #7: crashed: general protection fault in send_hsr_supervision_frame
run #8: crashed: WARNING: refcount bug in nr_insert_socket
run #9: OK
# git bisect bad 946c8eb20f5fce2069a12ef8fe414c0c21acac1d
Bisecting: 147 revisions left to test after this (roughly 7 steps)
[77485242e132859b7a3104357a282c349c6e0027] Merge remote-tracking branch 'phy/fixes'
testing commit 77485242e132859b7a3104357a282c349c6e0027 with gcc (GCC) 8.1.0
run #0: crashed: KASAN: use-after-free Read in nr_insert_socket
run #1: crashed: KASAN: use-after-free Read in nr_insert_socket
run #2: crashed: WARNING: refcount bug in nr_insert_socket
run #3: crashed: KASAN: use-after-free Read in nr_insert_socket
run #4: crashed: KASAN: use-after-free Read in lock_sock_nested
run #5: crashed: general protection fault in send_hsr_supervision_frame
run #6: crashed: KASAN: use-after-free Read in nr_release
run #7: crashed: WARNING: refcount bug in nr_insert_socket
run #8: crashed: KASAN: use-after-free Read in nr_insert_socket
run #9: OK
# git bisect bad 77485242e132859b7a3104357a282c349c6e0027
Bisecting: 75 revisions left to test after this (roughly 6 steps)
[0d581ba311a27762fe1a14e5db5f65d225b3d844] net: hns: add support for vlan TSO
testing commit 0d581ba311a27762fe1a14e5db5f65d225b3d844 with gcc (GCC) 8.1.0
run #0: crashed: WARNING: refcount bug in nr_insert_socket
run #1: crashed: KASAN: use-after-free Read in lock_sock_nested
run #2: crashed: WARNING: refcount bug in nr_insert_socket
run #3: crashed: WARNING: refcount bug in nr_insert_socket
run #4: crashed: KASAN: use-after-free Read in lock_sock_nested
run #5: crashed: WARNING: refcount bug in nr_insert_socket
run #6: crashed: WARNING: refcount bug in nr_insert_socket
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 0d581ba311a27762fe1a14e5db5f65d225b3d844
Bisecting: 36 revisions left to test after this (roughly 5 steps)
[1dbc59fa4bbaa108b641cd65a54f662b75e4ed36] bnxt_en: Cap the returned MSIX vectors to the RDMA driver.
testing commit 1dbc59fa4bbaa108b641cd65a54f662b75e4ed36 with gcc (GCC) 8.1.0
all runs: OK
# git bisect good 1dbc59fa4bbaa108b641cd65a54f662b75e4ed36
Bisecting: 18 revisions left to test after this (roughly 4 steps)
[8a534f8fb0dc44694a437b575060499efd1c91de] Merge branch 'idr-fix-overflow-cases-on-32-bit-CPU'
testing commit 8a534f8fb0dc44694a437b575060499efd1c91de with gcc (GCC) 8.1.0
run #0: crashed: WARNING: refcount bug in nr_insert_socket
run #1: crashed: WARNING: refcount bug in nr_insert_socket
run #2: crashed: WARNING: refcount bug in nr_insert_socket
run #3: crashed: KASAN: use-after-free Read in lock_sock_nested
run #4: crashed: KASAN: use-after-free Read in lock_sock_nested
run #5: crashed: KASAN: use-after-free Read in lock_sock_nested
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 8a534f8fb0dc44694a437b575060499efd1c91de
Bisecting: 8 revisions left to test after this (roughly 3 steps)
[4d1415811e492d9a8238f8a92dd0d51612c788e9] sctp: fix error handling on stream scheduler initialization
testing commit 4d1415811e492d9a8238f8a92dd0d51612c788e9 with gcc (GCC) 8.1.0
run #0: crashed: WARNING: refcount bug in nr_insert_socket
run #1: crashed: WARNING: refcount bug in nr_insert_socket
run #2: crashed: KASAN: use-after-free Read in lock_sock_nested
run #3: crashed: WARNING: refcount bug in nr_insert_socket
run #4: crashed: WARNING: refcount bug in nr_insert_socket
run #5: crashed: KASAN: use-after-free Read in lock_sock_nested
run #6: crashed: KASAN: use-after-free Read in lock_sock_nested
run #7: OK
run #8: OK
run #9: OK
# git bisect bad 4d1415811e492d9a8238f8a92dd0d51612c788e9
Bisecting: 4 revisions left to test after this (roughly 2 steps)
[dca895b65d634f9e6506d5385ed58a8b9abd4900] Documentation/networking: fix default_ttl typo in mpls-sysctl
testing commit dca895b65d634f9e6506d5385ed58a8b9abd4900 with gcc (GCC) 8.1.0
all runs: OK
# git bisect good dca895b65d634f9e6506d5385ed58a8b9abd4900
Bisecting: 2 revisions left to test after this (roughly 1 step)
[88405680ec57c35f5886dbb81b3f6f638f74f40d] net:gue.h:Fix shifting signed 32-bit value by 31 bits problem
testing commit 88405680ec57c35f5886dbb81b3f6f638f74f40d with gcc (GCC) 8.1.0
all runs: OK
# git bisect good 88405680ec57c35f5886dbb81b3f6f638f74f40d
Bisecting: 0 revisions left to test after this (roughly 1 step)
[c8c8218ec5af5d2598381883acbefbf604e56b5e] netrom: fix a memory leak in nr_rx_frame()
testing commit c8c8218ec5af5d2598381883acbefbf604e56b5e with gcc (GCC) 8.1.0
run #0: crashed: WARNING: refcount bug in nr_insert_socket
run #1: crashed: KASAN: use-after-free Read in lock_sock_nested
run #2: crashed: WARNING: refcount bug in nr_insert_socket
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
# git bisect bad c8c8218ec5af5d2598381883acbefbf604e56b5e
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[2e60546368165c2449564d71f6005dda9205b5fb] ipv4: don't set IPv6 only flags to IPv4 addresses
testing commit 2e60546368165c2449564d71f6005dda9205b5fb with gcc (GCC) 8.1.0
all runs: OK
# git bisect good 2e60546368165c2449564d71f6005dda9205b5fb
c8c8218ec5af5d2598381883acbefbf604e56b5e is the first bad commit
commit c8c8218ec5af5d2598381883acbefbf604e56b5e
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date:   Thu Jun 27 14:30:58 2019 -0700

    netrom: fix a memory leak in nr_rx_frame()
    
    When the skb is associated with a new sock, just assigning
    it to skb->sk is not sufficient, we have to set its destructor
    to free the sock properly too.
    
    Reported-by: syzbot+d6636a36d3c34bd88938@syzkaller.appspotmail.com
    Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

:040000 040000 4c07dae2c063172c527c8acf843b916a275a70ce 1c43141d5e0b704990d869e2ed626126f1596f0b M	net
revisions tested: 17, total time: 5h0m47.061477704s (build: 1h36m40.716328379s, test: 3h18m39.499656448s)
first bad commit: c8c8218ec5af5d2598381883acbefbf604e56b5e netrom: fix a memory leak in nr_rx_frame()
cc: ["davem@davemloft.net" "linux-hams@vger.kernel.org" "linux-kernel@vger.kernel.org" "netdev@vger.kernel.org" "ralf@linux-mips.org" "xiyou.wangcong@gmail.com"]
crash: WARNING: refcount bug in nr_insert_socket
------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 0 PID: 0 at lib/refcount.c:156 refcount_inc_checked+0x2b/0x30 lib/refcount.c:156
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0-rc6+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x113/0x167 lib/dump_stack.c:113
 panic+0x212/0x4cb kernel/panic.c:219
 __warn.cold.8+0x1b/0x38 kernel/panic.c:576
 report_bug+0x1a4/0x200 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:291
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986
RIP: 0010:refcount_inc_checked+0x2b/0x30 lib/refcount.c:156
Code: 48 89 e5 e8 97 fe ff ff 84 c0 74 02 5d c3 80 3d 93 69 f3 05 00 75 f5 48 c7 c7 00 52 41 87 c6 05 83 69 f3 05 01 e8 a8 d2 3d fe <0f> 0b 5d c3 90 55 48 89 e5 41 56 41 55 49 89 fd 48 c7 c7 60 52 41
RSP: 0018:ffff8880aea09c10 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888098d03480 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff8827a8e8 RDI: ffffffff89d60d40
RBP: ffff8880aea09c10 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809852e7c0
R13: ffff888098d034e8 R14: 000000000000001d R15: ffff888098d0391e
 sock_hold include/net/sock.h:649 [inline]
 sk_add_node include/net/sock.h:701 [inline]
 nr_insert_socket+0x28/0xd0 net/netrom/af_netrom.c:137
 nr_rx_frame+0x160f/0x1f00 net/netrom/af_netrom.c:1023
 nr_loopback_timer+0x64/0x120 net/netrom/nr_loopback.c:59
 call_timer_fn+0x14d/0x510 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 run_timer_softirq+0xc6f/0x1330 kernel/time/timer.c:1698
 __do_softirq+0x260/0x958 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x13e/0x540 arch/x86/kernel/apic/apic.c:1068
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:native_safe_halt+0x12/0x20 arch/x86/include/asm/irqflags.h:61
Code: 11 ff ff ff 4c 89 e7 e8 6c f2 f4 fa eb 97 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 e9 07 00 00 00 0f 00 2d f0 41 64 00 fb f4 <5d> c3 66 90 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 e9 07 00 00
RSP: 0018:ffffffff88207ce0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: ffffffff8827a040 RCX: 0000000000000000
RDX: 1ffffffff10643e1 RSI: 0000000000000006 RDI: ffffffff88321f08
RBP: ffffffff88207ce0 R08: 0000000000000006 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff88321ef8 R14: 0000000000000000 R15: ffffffff88f68438
 arch_safe_halt arch/x86/include/asm/paravirt.h:156 [inline]
 default_idle+0x51/0x310 arch/x86/kernel/process.c:580
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
 default_idle_call+0x6d/0x90 kernel/sched/idle.c:94
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x3e4/0x590 kernel/sched/idle.c:263
 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:354
 rest_init+0x1a4/0x279 init/main.c:451
 arch_call_rest_init+0x9/0xc
 start_kernel+0x6bd/0x6f8 init/main.c:761
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470
 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243
Kernel Offset: disabled
Rebooting in 86400 seconds..