KASAN: user-memory-access Read in kvmclock_cpufreq_notifier

KASAN: user-memory-access Read in kvmclock_cpufreq_notifier

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    e6e6ec48 Merge tag 'fscrypt-for-linus' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=163a5753e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c2e311dba9a02ba9
dashboard link: https://syzkaller.appspot.com/bug?extid=59cd93bc8960efdbae86
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=144d1619e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=115c4475e00000

Bisection is inconclusive: the bug happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=165b512de00000
final crash:    https://syzkaller.appspot.com/x/report.txt?x=155b512de00000
console output: https://syzkaller.appspot.com/x/log.txt?x=115b512de00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+59cd93bc8960efdbae86@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: user-memory-access in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: user-memory-access in __kvmclock_cpufreq_notifier arch/x86/kvm/x86.c:7133 [inline]
BUG: KASAN: user-memory-access in kvmclock_cpufreq_notifier+0x1e9/0x580 arch/x86/kvm/x86.c:7172
Read of size 4 at addr 00000000896bb8f0 by task syz-executor372/10372

CPU: 0 PID: 10372 Comm: syz-executor372 Not tainted 5.6.0-rc5-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+0x5/0x32 mm/kasan/report.c:510
 kasan_report+0xe/0x20 mm/kasan/common.c:641
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x128/0x190 mm/kasan/generic.c:192
 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
 __kvmclock_cpufreq_notifier arch/x86/kvm/x86.c:7133 [inline]
 kvmclock_cpufreq_notifier+0x1e9/0x580 arch/x86/kvm/x86.c:7172
 </IRQ>
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 10372 Comm: syz-executor372 Tainted: G    B             5.6.0-rc5-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+0x43/0x49 mm/kasan/report.c:96
 __kasan_report.cold+0xd/0x32 mm/kasan/report.c:513
 kasan_report+0xe/0x20 mm/kasan/common.c:641
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x128/0x190 mm/kasan/generic.c:192
 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
 __kvmclock_cpufreq_notifier arch/x86/kvm/x86.c:7133 [inline]
 kvmclock_cpufreq_notifier+0x1e9/0x580 arch/x86/kvm/x86.c:7172
 </IRQ>
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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