KASAN: null-ptr-deref Read in uncore_pmu_event

KASAN: null-ptr-deref Read in uncore_pmu_event_add
Status: upstream: reported C repro on 2020/05/05 00:56
Reported-by: syzbot+832ccf42c61e3c63654e@syzkaller.appspotmail.com
First crash: 33d, last: 33d

Cause bisection: the bug happens on the oldest tested release
Crash: WARNING in sysfs_warn_dup (log)
Repro: C syz .config

Sample crash report:

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:56 [inline]
BUG: KASAN: null-ptr-deref in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
BUG: KASAN: null-ptr-deref in uncore_msr_perf_ctr arch/x86/events/intel/uncore.h:335 [inline]
BUG: KASAN: null-ptr-deref in uncore_perf_ctr arch/x86/events/intel/uncore.h:378 [inline]
BUG: KASAN: null-ptr-deref in uncore_assign_hw_event arch/x86/events/intel/uncore.c:230 [inline]
BUG: KASAN: null-ptr-deref in uncore_pmu_event_add+0xa25/0x16d0 arch/x86/events/intel/uncore.c:602
Read of size 8 at addr 0000000000000000 by task syz-executor764/7073

CPU: 0 PID: 7073 Comm: syz-executor764 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
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+0x188/0x20d lib/dump_stack.c:118
 __kasan_report.cold+0x5/0x4d mm/kasan/report.c:515
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 check_memory_region_inline mm/kasan/generic.c:187 [inline]
 check_memory_region+0x141/0x190 mm/kasan/generic.c:193
 instrument_atomic_read include/linux/instrumented.h:56 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
 uncore_msr_perf_ctr arch/x86/events/intel/uncore.h:335 [inline]
 uncore_perf_ctr arch/x86/events/intel/uncore.h:378 [inline]
 uncore_assign_hw_event arch/x86/events/intel/uncore.c:230 [inline]
 uncore_pmu_event_add+0xa25/0x16d0 arch/x86/events/intel/uncore.c:602
 </IRQ>
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 7073 Comm: syz-executor764 Tainted: G    B             5.7.0-rc1-next-20200415-syzkaller #0
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+0x188/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 end_report+0x4d/0x53 mm/kasan/report.c:103
 __kasan_report.cold+0xd/0x4d mm/kasan/report.c:518
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 check_memory_region_inline mm/kasan/generic.c:187 [inline]
 check_memory_region+0x141/0x190 mm/kasan/generic.c:193
 instrument_atomic_read include/linux/instrumented.h:56 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
 uncore_msr_perf_ctr arch/x86/events/intel/uncore.h:335 [inline]
 uncore_perf_ctr arch/x86/events/intel/uncore.h:378 [inline]
 uncore_assign_hw_event arch/x86/events/intel/uncore.c:230 [inline]
 uncore_pmu_event_add+0xa25/0x16d0 arch/x86/events/intel/uncore.c:602
 </IRQ>
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-linux-next-kasan-gce-root	2020/05/01 00:48	linux-next	ac935d22	3698959a	.config	log	report	syz	C	acme@kernel.org, alexander.shishkin@linux.intel.com, bp@alien8.de, hpa@zytor.com, jolsa@redhat.com, linux-kernel@vger.kernel.org, mark.rutland@arm.com, mingo@redhat.com, namhyung@kernel.org, peterz@infradead.org, tglx@linutronix.de, x86@kernel.org