WARNING in arch_install_hw

WARNING in arch_install_hw_breakpoint
Status: fixed on 2020/11/16 12:12
Reported-by: syzbot+370a6b0f11867bf13515@syzkaller.appspotmail.com
Fix commit: e898e69d x86/hw_breakpoints: Make default case in hw_breakpoint_arch_parse() return an error
First crash: 708d, last: 591d

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in arch_install_hw_breakpoint (log)
Repro: syz .config

Fix bisection: fixed by (bisect log) :
commit b3e5838252665ee4cfa76b82bdf1198dca81e5be
Author: Christian Brauner <christian@brauner.io>
Date: Wed Mar 27 12:04:15 2019 +0000

clone: add CLONE_PIDFD

similar bugs (3):
Kernel	Title	Repro	Fix bisect	Count	Last	Reported	Patched	Status
android-414	WARNING in arch_install_hw_breakpoint	syz		2	708d	687d	0/1	public: reported syz repro on 2019/04/13 00:01
linux-4.14	WARNING in arch_install_hw_breakpoint	syz	inconclusive	1	260d	590d	0/1	upstream: reported syz repro on 2019/07/19 00:15
android-49	WARNING in arch_install_hw_breakpoint	syz		3	591d	686d	0/3	public: reported syz repro on 2019/04/14 09:28

Sample crash report:

------------[ cut here ]------------
Can't find any breakpoint slot
WARNING: CPU: 0 PID: 8639 at arch/x86/kernel/hw_breakpoint.c:121 arch_install_hw_breakpoint+0x2d6/0x3a0 arch/x86/kernel/hw_breakpoint.c:121
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8639 Comm: syz-executor117 Not tainted 5.1.0-rc1+ #33
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+0x172/0x1f0 lib/dump_stack.c:113
 panic+0x2cb/0x65c kernel/panic.c:214
 __warn.cold+0x20/0x45 kernel/panic.c:571
 report_bug+0x263/0x2b0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:arch_install_hw_breakpoint+0x2d6/0x3a0 arch/x86/kernel/hw_breakpoint.c:121
Code: c8 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b 0f 0b 48 c7 c7 40 23 65 87 89 45 d4 c6 05 ed 9d 32 08 01 e8 98 43 1b 00 <0f> 0b 8b 45 d4 e9 bc fd ff ff 40 88 75 c8 e8 a7 8e 80 00 0f b6 75
RSP: 0018:ffff88807537f6d8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: ffff8880ae81ec98 RCX: 0000000000000000
RDX: 0000000040000000 RSI: ffffffff815ae266 RDI: ffffed100ea6fecd
RBP: ffff88807537f718 R08: ffff88809bb5c3c0 R09: fffffbfff11335f5
R10: fffffbfff11335f4 R11: ffffffff8899afa3 R12: ffff8880964a8940
R13: dffffc0000000000 R14: 0000000000000004 R15: 000000000001eca0
 hw_breakpoint_add+0xa7/0x130 kernel/events/hw_breakpoint.c:632
 event_sched_in kernel/events/core.c:2281 [inline]
 event_sched_in.isra.0+0x373/0xbf0 kernel/events/core.c:2245
 group_sched_in+0xe4/0x3d0 kernel/events/core.c:2317
 flexible_sched_in+0x615/0x9c0 kernel/events/core.c:3311
 visit_groups_merge+0x336/0x5d0 kernel/events/core.c:3259
 ctx_flexible_sched_in kernel/events/core.c:3345 [inline]
 ctx_sched_in+0x330/0x670 kernel/events/core.c:3390
 perf_event_sched_in+0x6e/0xa0 kernel/events/core.c:2426
 perf_event_context_sched_in kernel/events/core.c:3430 [inline]
 __perf_event_task_sched_in+0x609/0x820 kernel/events/core.c:3469
 perf_event_task_sched_in include/linux/perf_event.h:1115 [inline]
 finish_task_switch+0x2c2/0x780 kernel/sched/core.c:2725
 context_switch kernel/sched/core.c:2880 [inline]
 __schedule+0x81f/0x1cc0 kernel/sched/core.c:3518
 schedule+0x92/0x180 kernel/sched/core.c:3562
 freezable_schedule include/linux/freezer.h:172 [inline]
 ptrace_stop+0x3fe/0x950 kernel/signal.c:2111
 do_jobctl_trap kernel/signal.c:2330 [inline]
 get_signal+0x1502/0x1d50 kernel/signal.c:2456
 do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446e59
Code: e8 dc e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 2b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1dd1a82db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000129
RAX: 0000000000000000 RBX: 00000000006dcc28 RCX: 0000000000446e59
RDX: 0000000000000016 RSI: 00000000000021bf RDI: 00000000000021bf
RBP: 00000000006dcc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000100 R11: 0000000000000246 R12: 00000000006dcc2c
R13: 00007fff5f48179f R14: 00007f1dd1a839c0 R15: 20c49ba5e353f7cf

======================================================

Crashes (8):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kasan-gce-selinux-root	2019/03/23 07:18	upstream	fd1f297b	3361bde5	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2019/03/23 07:20	linux-next	e382d91f	3361bde5	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2019/07/18 22:57	upstream	22051d9c	7bb222f7	.config	log	report	syz
ci-upstream-kasan-gce-selinux-root	2019/07/18 22:42	upstream	22051d9c	7bb222f7	.config	log	report	syz
ci-upstream-kasan-gce-root	2019/07/18 21:04	upstream	22051d9c	7bb222f7	.config	log	report	syz
ci-upstream-kasan-gce-root	2019/03/23 18:06	upstream	a5ed1e96	a2cef203	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2019/03/23 07:04	upstream	fd1f297b	3361bde5	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2019/07/18 21:05	linux-next	6d21a41b	7bb222f7	.config	log	report	syz