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BUG: KASAN: slab-out-of-bounds in seq_buf_putmem+0xc9/0x180 lib/seq_buf.c:241
Read of size 1383 at addr ffff88801c0ecbe8 by task syz.1.2884/16954

CPU: 0 UID: 0 PID: 16954 Comm: syz.1.2884 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:186 [inline]
 kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200
 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105
 seq_buf_putmem+0xc9/0x180 lib/seq_buf.c:241
 trace_seq_putmem kernel/trace/trace_seq.c:296 [inline]
 trace_seq_putmem+0x11e/0x230 kernel/trace/trace_seq.c:284
 blk_trace_synthesize_old_trace kernel/trace/blktrace.c:1780 [inline]
 blk_trace_event_print_binary+0x13f/0x1b0 kernel/trace/blktrace.c:1788
 print_bin_fmt kernel/trace/trace.c:3152 [inline]
 print_trace_line+0xc9a/0x1790 kernel/trace/trace.c:3229
 tracing_read_pipe+0x586/0xd60 kernel/trace/trace.c:5446
 vfs_read+0x1e4/0xb40 fs/read_write.c:572
 ksys_read+0x12a/0x250 fs/read_write.c:716
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf705efec
Code: Unable to access opcode bytes at 0xf705efc2.
RSP: 002b:00000000f542c50c EFLAGS: 00000292 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000080001500
RDX: 00000000fffffe23 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c0ec
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x44100(__GFP_ZERO|__GFP_RETRY_MAYFAIL|__GFP_COMP), pid 0, tgid 0 (swapper), ts 904858969
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
 __alloc_pages_noprof mm/page_alloc.c:5471 [inline]
 alloc_pages_node_noprof+0x93/0x200 mm/page_alloc.c:5485
 alloc_cpu_data+0x20/0x120 kernel/trace/ring_buffer.c:446
 __rb_allocate_pages+0xb39/0xfc0 kernel/trace/ring_buffer.c:2517
 rb_allocate_pages kernel/trace/ring_buffer.c:2550 [inline]
 rb_allocate_cpu_buffer+0x9db/0x2780 kernel/trace/ring_buffer.c:2648
 alloc_buffer+0x66a/0x1690 kernel/trace/ring_buffer.c:2913
 __ring_buffer_alloc+0x2d/0x40 kernel/trace/ring_buffer.c:2959
 allocate_trace_buffer+0x150/0xa30 kernel/trace/trace.c:8465
 allocate_trace_buffers kernel/trace/trace.c:8498 [inline]
 tracer_alloc_buffers kernel/trace/trace.c:9910 [inline]
 early_trace_init+0x22d/0x5c0 kernel/trace/trace.c:10009
 start_kernel+0x1d3/0x490 init/main.c:1050
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x158
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88801c0ecf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88801c0ecf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88801c0ed000: 00 00 06 fc fc fc fc fc 00 00 01 fc fc fc fc fc
                         ^
 ffff88801c0ed080: 00 00 07 fc fc fc fc fc 00 00 07 fc fc fc fc fc
 ffff88801c0ed100: 00 00 03 fc fc fc fc fc 00 00 05 fc fc fc fc fc
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