WARNING in idr_alloc

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ddb429100000
kernel config: https://syzkaller.appspot.com/x/.config?x=d195fe572fb15312
dashboard link: https://syzkaller.appspot.com/bug?extid=f31428628ef672716ea8
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15252c4b100000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10159291100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+f31428...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 6830 at lib/idr.c:84 idr_alloc+0x11c/0x130 lib/idr.c:84
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 6830 Comm: syz-executor583 Not tainted 5.7.0-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+0x188/0x20d lib/dump_stack.c:118
panic+0x2e3/0x75c kernel/panic.c:221
__warn.cold+0x2f/0x35 kernel/panic.c:582
report_bug+0x27b/0x2f0 lib/bug.c:195
fixup_bug arch/x86/kernel/traps.c:105 [inline]
fixup_bug arch/x86/kernel/traps.c:100 [inline]
do_error_trap+0x12b/0x220 arch/x86/kernel/traps.c:197
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:216
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:idr_alloc+0x11c/0x130 lib/idr.c:84
Code: 00 00 00 44 89 e0 48 8b 4c 24 58 65 48 33 0c 25 28 00 00 00 75 1e 48 83 c4 60 5b 5d 41 5c 41 5d 41 5e 41 5f c3 e8 b4 6d c4 fd <0f> 0b 41 bc ea ff ff ff eb b7 e8 f5 6c 95 fd 0f 1f 44 00 00 41 57
RSP: 0018:ffffc90001077c68 EFLAGS: 00010293
RAX: ffff88809f48a580 RBX: 00000000ffff0301 RCX: ffffffff83af606b
RDX: 0000000000000000 RSI: ffffffff83af610c RDI: 0000000000000005
RBP: 1ffff9200020ef8d R08: ffff88809f48a580 R09: fffffbfff1516d79
R10: ffffffff8a8b6bc7 R11: fffffbfff1516d78 R12: 00000000ffff0300
R13: ffffffff8a837ae0 R14: ffff8880a1f7d640 R15: 0000000000000a20
qrtr_port_assign net/qrtr/qrtr.c:703 [inline]
__qrtr_bind.isra.0+0x12e/0x5c0 net/qrtr/qrtr.c:756
qrtr_bind+0x1c1/0x24a net/qrtr/qrtr.c:805
__sys_bind+0x20e/0x250 net/socket.c:1657
__do_sys_bind net/socket.c:1668 [inline]
__se_sys_bind net/socket.c:1666 [inline]
__x64_sys_bind+0x6f/0xb0 net/socket.c:1666
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x4401a9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffee5bbb0e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401a9
RDX: 000000000000000c RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a30
R13: 0000000000401ac0 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[syzbot]

syzbot has bisected this bug to:

commit e42671084361302141a09284fde9bbc14fdd16bf
Author: Manivannan Sadhasivam <manivannan...@linaro.org>
Date: Thu May 7 12:53:06 2020 +0000

net: qrtr: Do not depend on ARCH_QCOM

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17325ad5100000
start commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org..
git tree: upstream
final crash: https://syzkaller.appspot.com/x/report.txt?x=14b25ad5100000
console output: https://syzkaller.appspot.com/x/log.txt?x=10b25ad5100000

kernel config: https://syzkaller.appspot.com/x/.config?x=d195fe572fb15312
dashboard link: https://syzkaller.appspot.com/bug?extid=f31428628ef672716ea8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15252c4b100000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10159291100000

Reported-by: syzbot+f31428...@syzkaller.appspotmail.com
Fixes: e42671084361 ("net: qrtr: Do not depend on ARCH_QCOM")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection