ci2 starts bisection 2025-04-27 15:31:11.198583749 +0000 UTC m=+165440.947925263 bisecting fixing commit since 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 building syzkaller on 16256247d9c41cf4980c36db3841ddd674a04b58 ensuring issue is reproducible on original commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 testing commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 5da9570ec5eda6c17d47c27fc22ff74ead1725e01a5aace47fc1dcc3f27b66b4 run #0: crashed: general protection fault in n_tty_flush_buffer run #1: crashed: general protection fault in n_tty_flush_buffer run #2: crashed: general protection fault in n_tty_flush_buffer run #3: crashed: general protection fault in n_tty_flush_buffer run #4: crashed: general protection fault in n_tty_flush_buffer run #5: crashed: general protection fault in n_tty_flush_buffer run #6: crashed: general protection fault in n_tty_flush_buffer run #7: crashed: general protection fault in n_tty_flush_buffer run #8: crashed: general protection fault in n_tty_flush_buffer run #9: crashed: general protection fault in n_tty_flush_buffer run #10: crashed: general protection fault in n_tty_flush_buffer run #11: crashed: general protection fault in n_tty_flush_buffer run #12: crashed: general protection fault in n_tty_flush_buffer run #13: crashed: general protection fault in n_tty_flush_buffer run #14: crashed: general protection fault in n_tty_flush_buffer run #15: crashed: general protection fault in n_tty_flush_buffer run #16: crashed: general protection fault in n_tty_flush_buffer run #17: crashed: general protection fault in n_tty_flush_buffer run #18: crashed: general protection fault in n_tty_flush_buffer run #19: OK representative crash: general protection fault in n_tty_flush_buffer, types: [UNKNOWN] check whether we can drop unnecessary instrumentation disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG KASAN], they are not needed testing commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 9481ac95e7bbd9d1f547d057afadfcc2be5f6cd18bdf5445a952d970080017f8 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #9: OK representative crash: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer, types: [UNKNOWN] the bug reproduces without the instrumentation disabling configs for [HANG LEAK UBSAN BUG KASAN LOCKDEP ATOMIC_SLEEP], they are not needed kconfig minimization: base=4788 full=6023 leaves diff=246 split chunks (needed=false): <246> split chunk #0 of len 246 into 5 parts testing without sub-chunk 1/5 disabling configs for [KASAN LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG], they are not needed testing commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: a1868a5eed4563312b179cdb3f604313e533c8a4291e928f19949865bc3eb44d all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer representative crash: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 2/5 disabling configs for [HANG LEAK UBSAN BUG KASAN LOCKDEP ATOMIC_SLEEP], they are not needed testing commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 0e59cdcf7ee3631d174ff0fb0b54eaf45c0de94b07d1dd00fc1e50b7d85cf671 all runs: OK false negative chance: 0.000 testing without sub-chunk 3/5 disabling configs for [LEAK UBSAN BUG KASAN LOCKDEP ATOMIC_SLEEP HANG], they are not needed testing commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: c1af6570c0d8ec9190bbdcc3261991ee7f76da49bac6256c9544567fd925f4e3 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer representative crash: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 4/5 disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG KASAN], they are not needed testing commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 8e914d871f4a94c5a9877ac45da08dda162061aefc73e38eb9b6afcc1db0bc16 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #9: OK representative crash: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 5/5 disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG KASAN], they are not needed testing commit 3f5f2283d6843bde6658e93fc50f5f00e5bd3595 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 0efe0765fa02234d666257c3b562f4666837114c9e930fc71a9a4203aa0689ed run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #9: OK representative crash: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer, types: [UNKNOWN] the chunk can be dropped minimized to 50 configs; suspects: [CFG80211 CPU_MITIGATIONS FB HID_HOLTEK HID_PANTHERLORD 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_MUX INPUT_JOYSTICK INPUT_LEDS INPUT_MOUSE INTEGRITY INTEGRITY_AUDIT JOYSTICK_XPAD JOYSTICK_XPAD_FF JOYSTICK_XPAD_LEDS KCOV KCOV_ENABLE_COMPARISONS KCOV_INSTRUMENT_ALL LCD_CLASS_DEVICE LD_IS_BFD LOGIG940_FF LOGIRUMBLEPAD2_FF LOGITECH_FF LOGIWHEELS_FF MAC80211 MAC80211_HAS_RC MAC80211_RC_DEFAULT_MINSTREL MAC80211_RC_MINSTREL MEDIA_ANALOG_TV_SUPPORT MEDIA_ATTACH MEDIA_DIGITAL_TV_SUPPORT MEDIA_RADIO_SUPPORT MEDIA_TUNER MFD_CORE MITIGATION_RFDS NL80211_TESTMODE NOP_USB_XCEIV PANTHERLORD_FF PROC_MEM_ALWAYS_FORCE RADIO_ADAPTERS REGMAP_SPI RFKILL SND SOUND VT WIRELESS] disabling configs for [UBSAN BUG KASAN LOCKDEP ATOMIC_SLEEP HANG LEAK], they are not needed testing current HEAD ba8b8b19339409d005e0b71075309daf1bbbcbb6 testing commit ba8b8b19339409d005e0b71075309daf1bbbcbb6 gcc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 6ad4f2b78299b62c59ceb43f8549b86aa1a0a4631557a7dd99c68e330e1f3e5c run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer run #9: OK representative crash: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer, types: [UNKNOWN] crash still not fixed/happens on the oldest tested release revisions tested: 8, total time: 3h59m20.924802581s (build: 1h17m27.870686251s, test: 1h48m50.950792886s) crash still not fixed or there were kernel test errors commit msg: Revert "can: statistics: use atomic access in hot path" crash: BUG: unable to handle kernel NULL pointer dereference in n_tty_flush_buffer BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 117867067 P4D 117867067 PUD 0 Oops: 0002 [#1] PREEMPT SMP CPU: 0 PID: 383 Comm: kworker/0:5 Not tainted 5.10.236-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events vc_SAK RIP: 0010:reset_buffer_flags drivers/tty/n_tty.c:332 [inline] RIP: 0010:n_tty_flush_buffer+0x36/0xa0 drivers/tty/n_tty.c:370 Code: e0 cc 7e ff 4d 8d ac 24 f0 00 00 00 4c 89 ef e8 b0 99 b5 00 49 8b 94 24 b8 02 00 00 31 c0 b9 40 00 00 00 48 8d b2 60 10 00 00 <48> c7 42 10 00 00 00 00 48 89 f7 48 c7 02 00 00 00 00 48 c7 82 60 RSP: 0018:ffffc900009d7d30 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffff81ae6180 RCX: 0000000000000040 RDX: 0000000000000000 RSI: 0000000000001060 RDI: ffff88811e1cc8f0 RBP: ffffc900009d7d40 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000001800 R12: ffff88811e1cc800 R13: ffff88811e1cc8f0 R14: ffff88811e1cc960 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 0000000109b22000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tty_buffer_flush+0x10f/0x140 drivers/tty/tty_buffer.c:239 tty_ldisc_flush+0x4c/0xa0 drivers/tty/tty_ldisc.c:415 __do_SAK.part.0+0x1e5/0x230 drivers/tty/tty_io.c:3001 __do_SAK+0x20/0x30 drivers/tty/tty_io.c:2994 vc_SAK+0x43/0xd0 drivers/tty/vt/vt_ioctl.c:994 process_one_work+0x23e/0x500 kernel/workqueue.c:2301 worker_thread+0x5c/0x530 kernel/workqueue.c:2447 kthread+0x196/0x1d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Modules linked in: CR2: 0000000000000010 ---[ end trace cdffb92593189607 ]--- RIP: 0010:reset_buffer_flags drivers/tty/n_tty.c:332 [inline] RIP: 0010:n_tty_flush_buffer+0x36/0xa0 drivers/tty/n_tty.c:370 Code: e0 cc 7e ff 4d 8d ac 24 f0 00 00 00 4c 89 ef e8 b0 99 b5 00 49 8b 94 24 b8 02 00 00 31 c0 b9 40 00 00 00 48 8d b2 60 10 00 00 <48> c7 42 10 00 00 00 00 48 89 f7 48 c7 02 00 00 00 00 48 c7 82 60 RSP: 0018:ffffc900009d7d30 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffff81ae6180 RCX: 0000000000000040 RDX: 0000000000000000 RSI: 0000000000001060 RDI: ffff88811e1cc8f0 RBP: ffffc900009d7d40 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000001800 R12: ffff88811e1cc800 R13: ffff88811e1cc8f0 R14: ffff88811e1cc960 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 0000000109b22000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: e0 cc loopne 0xffffffce 2: 7e ff jle 0x3 4: 4d 8d ac 24 f0 00 00 lea 0xf0(%r12),%r13 b: 00 c: 4c 89 ef mov %r13,%rdi f: e8 b0 99 b5 00 call 0xb599c4 14: 49 8b 94 24 b8 02 00 mov 0x2b8(%r12),%rdx 1b: 00 1c: 31 c0 xor %eax,%eax 1e: b9 40 00 00 00 mov $0x40,%ecx 23: 48 8d b2 60 10 00 00 lea 0x1060(%rdx),%rsi * 2a: 48 c7 42 10 00 00 00 movq $0x0,0x10(%rdx) <-- trapping instruction 31: 00 32: 48 89 f7 mov %rsi,%rdi 35: 48 c7 02 00 00 00 00 movq $0x0,(%rdx) 3c: 48 rex.W 3d: c7 .byte 0xc7 3e: 82 (bad) 3f: 60 (bad)