ci2 starts bisection 2025-12-19 05:02:19.191546054 +0000 UTC m=+1956751.368669131
bisecting fixing commit since 4cf22d97834887b6800b278f9862d78373d7fc5c
building syzkaller on e565f08d1cb546967f255601a17a0c958d06ce6d
ensuring issue is reproducible on original commit 4cf22d97834887b6800b278f9862d78373d7fc5c
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: a4fd3b96dc4afd9f83783183a336626e57506dd5f56a21ace755f9e96a8bb4bf
all runs: crashed: KASAN: null-ptr-deref Write in n_tty_flush_buffer
representative crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer, types: [KASAN-NULL-POINTER-DEREFERENCE-WRITE]
check whether we can drop unnecessary instrumentation
disabling configs for [bug_or_warning locking atomic_sleep hang memleak ubsan], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: 36cd5297292aae312e236296a6bf14a56e4920bf2a3232662ce70b1371778e62
all runs: crashed: KASAN: null-ptr-deref Write in n_tty_flush_buffer
representative crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer, types: [KASAN-NULL-POINTER-DEREFERENCE-WRITE]
the bug reproduces without the instrumentation
disabling configs for [bug_or_warning locking atomic_sleep hang memleak ubsan], they are not needed
kconfig minimization: base=5186 full=6555 leaves diff=264
split chunks (needed=false): <264>
split chunk #0 of len 264 into 5 parts
testing without sub-chunk 1/5
disabling configs for [locking atomic_sleep hang memleak ubsan bug_or_warning], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: 1dec2df01fad9178837cae6898912ff68feb6e83dcf548798763439ef573e3f3
all runs: crashed: KASAN: null-ptr-deref Write in n_tty_flush_buffer
representative crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer, types: [KASAN-NULL-POINTER-DEREFERENCE-WRITE]
the chunk can be dropped
testing without sub-chunk 2/5
disabling configs for [memleak ubsan bug_or_warning locking atomic_sleep hang], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: cf4ac1169a68e62d3cb338ab5168e2ea3d48eb9947b316bc4cf4b423f8f8f3a8
all runs: OK
false negative chance: 0.000
testing without sub-chunk 3/5
disabling configs for [ubsan bug_or_warning locking atomic_sleep hang memleak], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: ec15c4877a62314cf7d17f6ac882d61092c1ae1e9df0d714e2398134d170ce28
all runs: crashed: KASAN: null-ptr-deref Write in n_tty_flush_buffer
representative crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer, types: [KASAN-NULL-POINTER-DEREFERENCE-WRITE]
the chunk can be dropped
testing without sub-chunk 4/5
disabling configs for [atomic_sleep hang memleak ubsan bug_or_warning locking], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: 860067305a2dec3de476408ef067bcfb84d2a6e952fc1c1b290d99ed41618634
all runs: crashed: KASAN: null-ptr-deref Write in n_tty_flush_buffer
representative crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer, types: [KASAN-NULL-POINTER-DEREFERENCE-WRITE]
the chunk can be dropped
testing without sub-chunk 5/5
disabling configs for [locking atomic_sleep hang memleak ubsan bug_or_warning], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: d1de6529804ab652b8a1934b0459e8a36f9d09f90c3fd577f26f8c8bc3a89f7b
all runs: crashed: KASAN: null-ptr-deref Write in n_tty_flush_buffer
representative crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer, types: [KASAN-NULL-POINTER-DEREFERENCE-WRITE]
the chunk can be dropped
minimized to 53 configs; suspects: [CFG80211 COMMON_CLK CPU_MITIGATIONS FB HID_HOLTEK HID_NTI HID_NTRIG HID_ORTEK HID_PENMOUNT HID_PETALYNX HID_PICOLCD_FB HID_PICOLCD_LEDS HID_PID HID_PRIMAX HID_PRODIKEYS HID_RMI HID_SAITEK HID_SAMSUNG HID_SENSOR_CUSTOM_SENSOR HID_SENSOR_HUB HID_SPEEDLINK HID_STEELSERIES HID_SUNPLUS HID_THINGM HID_TIVO HID_TOPSEED HID_TWINHAN HID_WALTOP HID_XINMO HID_ZYDACRON HOLTEK_FF HOTPLUG_PCI HWMON HW_CONSOLE I2C_DESIGNWARE_CORE I2C_DESIGNWARE_PLATFORM I2C_MUX INPUT_JOYSTICK INPUT_LEDS INPUT_MOUSE INPUT_TOUCHSCREEN INTEGRITY INTEGRITY_AUDIT JOYSTICK_XPAD JOYSTICK_XPAD_FF JOYSTICK_XPAD_LEDS KCOV KCOV_ENABLE_COMPARISONS KCOV_INSTRUMENT_ALL LCD_CLASS_DEVICE LOCK_MM_AND_FIND_VMA LOGIG940_FF LOGIRUMBLEPAD2_FF LOGITECH_FF LOGIWHEELS_FF MAC80211 MEDIA_ANALOG_TV_SUPPORT MEDIA_ATTACH MEDIA_DIGITAL_TV_SUPPORT MEDIA_RADIO_SUPPORT MEDIA_TUNER MFD_CORE MITIGATION_RFDS MITIGATION_SPECTRE_BHI NETFILTER_FAMILY_BRIDGE NET_DEVLINK RFKILL SND SOUND VT WIRELESS]
disabling configs for [atomic_sleep hang memleak ubsan bug_or_warning locking], they are not needed
testing current HEAD 72ada78f601d704f44161ace443aa7cd03c257a7
testing commit 72ada78f601d704f44161ace443aa7cd03c257a7 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: b7458c656586027c35f4c9ceb01b1e6e25aee423440dab3ef78f2eac15ddb21c
all runs: crashed: KASAN: null-ptr-deref Write in n_tty_flush_buffer
representative crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer, types: [KASAN-NULL-POINTER-DEREFERENCE-WRITE]
crash still not fixed/happens on the oldest tested release
revisions tested: 8, total time: 1h49m8.34846409s (build: 34m5.192780868s, test: 1h6m36.046035714s)
crash still not fixed or there were kernel test errors
commit msg: Merge tag 'android14-6.1.158_r00' into android14-6.1
crash: KASAN: null-ptr-deref Write in n_tty_flush_buffer
==================================================================
BUG: KASAN: null-ptr-deref in reset_buffer_flags drivers/tty/n_tty.c:332 [inline]
BUG: KASAN: null-ptr-deref in n_tty_flush_buffer+0x72/0x390 drivers/tty/n_tty.c:371
Write of size 24 at addr 0000000000000000 by task kworker/0:0/6
CPU: 0 PID: 6 Comm: kworker/0:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events vc_SAK
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:88
dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106
print_report+0x3d/0x60 mm/kasan/report.c:423
kasan_report+0x122/0x150 mm/kasan/report.c:524
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
memset+0x23/0x40 mm/kasan/shadow.c:44
reset_buffer_flags drivers/tty/n_tty.c:332 [inline]
n_tty_flush_buffer+0x72/0x390 drivers/tty/n_tty.c:371
tty_buffer_flush+0x2f5/0x3c0 drivers/tty/tty_buffer.c:242
tty_ldisc_flush+0x6c/0xc0 drivers/tty/tty_ldisc.c:389
__do_SAK+0x132/0x640 drivers/tty/tty_io.c:3011
vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:995
process_one_work+0x6e9/0xdc0 kernel/workqueue.c:2302
worker_thread+0x9b3/0x10c0 kernel/workqueue.c:2449
kthread+0x243/0x2c0 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
==================================================================
BUG: unable to handle page fault for address: 0000000000002260
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 12d499067 P4D 12d499067 PUD 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 6 Comm: kworker/0:0 Tainted: G B syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events vc_SAK
RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64
Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
RSP: 0018:ffffc90000067b58 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000010
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000002260
RBP: ffffc90000067b78 R08: 0000000000000000 R09: 0000000000002260
R10: fffffbfff0d3e4fd R11: 1ffffffff0d3e4fc R12: 0000000000000000
R13: 000000000000005d R14: 0000000000000000 R15: 0000000000002260
FS: 0000000000000000(0000) GS:ffff8881f7200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000002260 CR3: 0000000120530000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
reset_buffer_flags drivers/tty/n_tty.c:334 [inline]
n_tty_flush_buffer+0x81/0x390 drivers/tty/n_tty.c:371
tty_buffer_flush+0x2f5/0x3c0 drivers/tty/tty_buffer.c:242
tty_ldisc_flush+0x6c/0xc0 drivers/tty/tty_ldisc.c:389
__do_SAK+0x132/0x640 drivers/tty/tty_io.c:3011
vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:995
process_one_work+0x6e9/0xdc0 kernel/workqueue.c:2302
worker_thread+0x9b3/0x10c0 kernel/workqueue.c:2449
kthread+0x243/0x2c0 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Modules linked in:
CR2: 0000000000002260
---[ end trace 0000000000000000 ]---
RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64
Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
RSP: 0018:ffffc90000067b58 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000010
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000002260
RBP: ffffc90000067b78 R08: 0000000000000000 R09: 0000000000002260
R10: fffffbfff0d3e4fd R11: 1ffffffff0d3e4fc R12: 0000000000000000
R13: 000000000000005d R14: 0000000000000000 R15: 0000000000002260
FS: 0000000000000000(0000) GS:ffff8881f7200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000002260 CR3: 0000000120530000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: c1 e9 03 shr $0x3,%ecx
3: 40 0f b6 f6 movzbl %sil,%esi
7: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax
e: 01 01 01
11: 48 0f af c6 imul %rsi,%rax
15: f3 48 ab rep stos %rax,%es:(%rdi)
18: 89 d1 mov %edx,%ecx
1a: f3 aa rep stos %al,%es:(%rdi)
1c: 4c 89 c8 mov %r9,%rax
1f: c3 ret
20: 90 nop
21: 49 89 f9 mov %rdi,%r9
24: 40 88 f0 mov %sil,%al
27: 48 89 d1 mov %rdx,%rcx
* 2a: f3 aa rep stos %al,%es:(%rdi) <-- trapping instruction
2c: 4c 89 c8 mov %r9,%rax
2f: c3 ret
30: 90 nop
31: 49 89 fa mov %rdi,%r10
34: 40 0f b6 ce movzbl %sil,%ecx
38: 48 rex.W
39: b8 01 01 01 01 mov $0x1010101,%eax
3e: 01 01 add %eax,(%rcx)