syzbot

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kernel BUG at ./include/linux/pagemap.h:1426!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 10049 Comm: syz.4.963 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__readahead_folio include/linux/pagemap.h:1426 [inline]
RIP: 0010:readahead_folio include/linux/pagemap.h:1452 [inline]
RIP: 0010:mpage_readahead+0x4ad/0x5a0 fs/mpage.c:367
Code: 5e 41 5f e9 c5 6d 29 09 e8 90 20 6d ff 48 89 ef e8 08 cf aa ff e9 54 fe ff ff 4c 8b 6c 24 18 e9 43 ff ff ff e8 74 20 6d ff 90 <0f> 0b e8 6c 20 6d ff 48 c7 c6 80 64 a1 8b 48 89 ef e8 5d fd b7 ff
RSP: 0018:ffffc9000f2cf240 EFLAGS: 00010283
RAX: 0000000000004f58 RBX: ffffc9000f2cf6f8 RCX: ffffc90011796000
RDX: 0000000000080000 RSI: ffffffff8251c5fc RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000004 R09: 0000000000000004
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: fffff52001e59ee3 R14: 0000000000000001 R15: 1ffff92001e59ee3
FS:  00007f25468c26c0(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f77147156c0 CR3: 00000000380a7000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 read_pages+0x1c4/0xc70 mm/readahead.c:163
 page_cache_ra_unbounded+0x66c/0x9e0 mm/readahead.c:269
 do_page_cache_ra mm/readahead.c:332 [inline]
 page_cache_ra_order+0xbf4/0xed0 mm/readahead.c:535
 do_sync_mmap_readahead mm/filemap.c:3400 [inline]
 filemap_fault+0x16ac/0x29d0 mm/filemap.c:3549
 __do_fault+0x10d/0x490 mm/memory.c:5320
 do_shared_fault mm/memory.c:5819 [inline]
 do_fault+0x302/0x1ad0 mm/memory.c:5893
 do_pte_missing mm/memory.c:4401 [inline]
 handle_pte_fault mm/memory.c:6273 [inline]
 __handle_mm_fault+0x1919/0x2bb0 mm/memory.c:6411
 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6580
 do_user_addr_fault+0x7a6/0x1370 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:74
Code: 81 04 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 73 e8 eb c5 <f3> a4 c3 cc cc cc cc 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48
RSP: 0018:ffffc9000f2cfbb0 EFLAGS: 00050202
RAX: 0000000000000001 RBX: 00000000000000e4 RCX: 00000000000000e4
RDX: ffffed100ac2731d RSI: ffff888056139800 RDI: 000020000000056c
RBP: 000020000000056c R08: 0000000000000000 R09: ffffed100ac2731c
R10: ffff8880561398e3 R11: 0000000000000000 R12: ffff888056139800
R13: 0000200000000650 R14: 00007ffffffff000 R15: 0000000000000000
 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline]
 _inline_copy_to_user include/linux/uaccess.h:206 [inline]
 _copy_to_user+0xbb/0xd0 lib/usercopy.c:26
 copy_to_user include/linux/uaccess.h:236 [inline]
 snd_pcm_oss_read2+0x294/0x410 sound/core/oss/pcm_oss.c:1485
 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1538 [inline]
 snd_pcm_oss_read+0x5d2/0x760 sound/core/oss/pcm_oss.c:2771
 vfs_read+0x1e4/0xcf0 fs/read_write.c:570
 ksys_read+0x12a/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f254598f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f25468c2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f2545be6180 RCX: 00007f254598f749
RDX: 0000000000001000 RSI: 00002000000002c0 RDI: 0000000000000009
RBP: 00007f2545a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2545be6218 R14: 00007f2545be6180 R15: 00007fff0d1d5d28
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__readahead_folio include/linux/pagemap.h:1426 [inline]
RIP: 0010:readahead_folio include/linux/pagemap.h:1452 [inline]
RIP: 0010:mpage_readahead+0x4ad/0x5a0 fs/mpage.c:367
Code: 5e 41 5f e9 c5 6d 29 09 e8 90 20 6d ff 48 89 ef e8 08 cf aa ff e9 54 fe ff ff 4c 8b 6c 24 18 e9 43 ff ff ff e8 74 20 6d ff 90 <0f> 0b e8 6c 20 6d ff 48 c7 c6 80 64 a1 8b 48 89 ef e8 5d fd b7 ff
RSP: 0018:ffffc9000f2cf240 EFLAGS: 00010283
RAX: 0000000000004f58 RBX: ffffc9000f2cf6f8 RCX: ffffc90011796000
RDX: 0000000000080000 RSI: ffffffff8251c5fc RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000004 R09: 0000000000000004
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: fffff52001e59ee3 R14: 0000000000000001 R15: 1ffff92001e59ee3
FS:  00007f25468c26c0(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7713be7dac CR3: 00000000380a7000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	04 00                	add    $0x0,%al
   2:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
   9:	00 00 00 00
   d:	66 90                	xchg   %ax,%ax
   f:	48 8b 06             	mov    (%rsi),%rax
  12:	48 89 07             	mov    %rax,(%rdi)
  15:	48 83 c6 08          	add    $0x8,%rsi
  19:	48 83 c7 08          	add    $0x8,%rdi
  1d:	83 e9 08             	sub    $0x8,%ecx
  20:	74 db                	je     0xfffffffd
  22:	83 f9 08             	cmp    $0x8,%ecx
  25:	73 e8                	jae    0xf
  27:	eb c5                	jmp    0xffffffee
* 29:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
  2b:	c3                   	ret
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	48 8b 06             	mov    (%rsi),%rax
  33:	48 89 07             	mov    %rax,(%rdi)
  36:	48 8d 47 08          	lea    0x8(%rdi),%rax
  3a:	48 83 e0 f8          	and    $0xfffffffffffffff8,%rax
  3e:	48                   	rex.W