================================================================== 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+0x6c/0x220 drivers/tty/n_tty.c:371 Write of size 24 at addr 0000000000000000 by task kworker/0:3/510 CPU: 0 PID: 510 Comm: kworker/0:3 Not tainted 6.1.138-syzkaller-00049-g5b87067cdd87 #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+0x6c/0x220 drivers/tty/n_tty.c:371 tty_buffer_flush+0x31d/0x3e0 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+0x71f/0xc40 kernel/workqueue.c:2299 worker_thread+0xa29/0x11f0 kernel/workqueue.c:2446 kthread+0x281/0x320 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 124a5e067 P4D 124a5e067 PUD 10d6ac067 PMD 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 0 PID: 510 Comm: kworker/0:3 Tainted: G B 6.1.138-syzkaller-00049-g5b87067cdd87 #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:ffffc90001257b50 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000010 RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000002260 RBP: ffffc90001257b70 R08: 0000000000000000 R09: 0000000000002260 R10: fffffbfff0f2cafd R11: 1ffffffff0f2cafc R12: 000000000000005d R13: 0000000000002260 R14: 0000000000000000 R15: 0000000000002260 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000002260 CR3: 000000010d160000 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+0x7b/0x220 drivers/tty/n_tty.c:371 tty_buffer_flush+0x31d/0x3e0 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+0x71f/0xc40 kernel/workqueue.c:2299 worker_thread+0xa29/0x11f0 kernel/workqueue.c:2446 kthread+0x281/0x320 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:ffffc90001257b50 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000010 RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000002260 RBP: ffffc90001257b70 R08: 0000000000000000 R09: 0000000000002260 R10: fffffbfff0f2cafd R11: 1ffffffff0f2cafc R12: 000000000000005d R13: 0000000000002260 R14: 0000000000000000 R15: 0000000000002260 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000002260 CR3: 000000010d160000 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)