ci2 starts bisection 2025-07-20 17:34:46.276705833 +0000 UTC m=+164670.216331190
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 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 8f42328eb63e1788b26f4c738e8dc7a7c03e316282e45e7e83c1317c141effe3
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 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 383271e50c416924a355f4cab8fb2afde41499f351a746d335095f42824d7a1c
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 [locking atomic_sleep hang memleak ubsan bug_or_warning], 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 [hang memleak ubsan bug_or_warning locking atomic_sleep], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: e05fc6658c5c59aa9dec6bcee04d1bb487ad8a53ffd01e61f017c770bf67e263
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 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 0964c0c2512edc5bfd0616fda2af0c822e9ff76f8df555c0af5313af8b647402
all runs: OK
false negative chance: 0.000
testing without sub-chunk 3/5
disabling configs for [hang memleak ubsan bug_or_warning locking atomic_sleep], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: c118ce6ffa50a3dc790cb2b5c25dde3fb15845e3cb1ca4f8ae8665a08f835f15
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 [ubsan bug_or_warning locking atomic_sleep hang memleak], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 74c91e7298f4f8d345a97e453fa0c30157294ae793c9e41dc030da639ef6c34e
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 [memleak ubsan bug_or_warning locking atomic_sleep hang], they are not needed
testing commit 4cf22d97834887b6800b278f9862d78373d7fc5c gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 7d5932eda57817e710239f6d69e744a578b59afde8669f24688d4ceb27b4f264
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 [bug_or_warning locking atomic_sleep hang memleak ubsan], they are not needed
testing current HEAD 145c7fad733f13d7a8f4aa156785f40d38e966da
testing commit 145c7fad733f13d7a8f4aa156785f40d38e966da gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 5dec6e4edbc3a5cb2b19201f00f57092a54c0a1037403b77e97e8fdb76769f71
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: 2h57m26.2775686s (build: 1h33m59.183267323s, test: 1h12m15.498721508s)
crash still not fixed or there were kernel test errors
commit msg: ANDROID: gki_defconfig: Enable CONFIG_UDMABUF
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/0:4/498
CPU: 0 PID: 498 Comm: kworker/0:4 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:430
kasan_report+0x122/0x150 mm/kasan/report.c:531
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:2299
worker_thread+0x9b3/0x10c0 kernel/workqueue.c:2446
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 10dfc3067 P4D 10dfc3067 PUD 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 498 Comm: kworker/0:4 Tainted: G B 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:ffffc90000d37b58 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000010
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000002260
RBP: ffffc90000d37b78 R08: 0000000000000000 R09: 0000000000002260
R10: fffffbfff0cfd8fd R11: 1ffffffff0cfd8fc 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: 00000001215ab000 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:2299
worker_thread+0x9b3/0x10c0 kernel/workqueue.c:2446
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:ffffc90000d37b58 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000010
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000002260
RBP: ffffc90000d37b78 R08: 0000000000000000 R09: 0000000000002260
R10: fffffbfff0cfd8fd R11: 1ffffffff0cfd8fc 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: 00000001215ab000 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)