syzbot


KASAN: wild-memory-access Read in page_add_file_rmap

Status: premoderation: reported on 2026/01/10 12:38
Reported-by: syzbot+2805887d538c326f8a21@syzkaller.appspotmail.com
First crash: 2d21h, last: 2d21h

Sample crash report:
==================================================================
BUG: KASAN: wild-memory-access in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: wild-memory-access in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
BUG: KASAN: wild-memory-access in lock_page_memcg+0xa6/0x1c0 mm/memcontrol.c:2153
Read of size 4 at addr 00ff8881280e89c0 by task syz.6.6812/25615

CPU: 1 PID: 25615 Comm: syz.6.6812 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 __kasan_report mm/kasan/report.c:439 [inline]
 kasan_report+0xd8/0x130 mm/kasan/report.c:452
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
 lock_page_memcg+0xa6/0x1c0 mm/memcontrol.c:2153
 page_add_file_rmap+0x2e/0x5d0 mm/rmap.c:1224
 do_set_pte+0x365/0x460 mm/memory.c:4196
 filemap_map_pages+0x5dd/0x1270 mm/filemap.c:3065
 do_fault_around mm/memory.c:4378 [inline]
 do_read_fault mm/memory.c:4393 [inline]
 do_fault mm/memory.c:4527 [inline]
 handle_pte_fault+0x1ae5/0x3750 mm/memory.c:4791
 __handle_mm_fault mm/memory.c:4944 [inline]
 handle_mm_fault+0xf3f/0x16a0 mm/memory.c:5358
 faultin_page mm/gup.c:902 [inline]
 __get_user_pages+0xbe9/0x13e0 mm/gup.c:1121
 __get_user_pages_locked mm/gup.c:1307 [inline]
 get_dump_page+0x169/0x5b0 mm/gup.c:1586
 dump_user_range+0x3c/0x1a0 fs/coredump.c:904
 elf_core_dump+0x278a/0x2bc0 fs/binfmt_elf.c:2290
 do_coredump+0x1ac9/0x27f0 fs/coredump.c:817
 get_signal+0xf23/0x12e0 kernel/signal.c:2779
 arch_do_signal_or_restart+0xbf/0x10f0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199
 irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:287
 irqentry_exit+0x12/0x60 kernel/entry/common.c:375
 exc_page_fault+0x67/0xc0 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
RIP: 0033:0x7f1929209751
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:00000000fffffe10 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f1929460090 RCX: 00007f1929209749
RDX: 0000000000000000 RSI: 00000000fffffe10 RDI: 0000000000000000
RBP: 00007f192928df91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1929460128 R14: 00007f1929460090 R15: 00007ffceef7c5f8
==================================================================
general protection fault, probably for non-canonical address 0xe01fed102501d138: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0x00ff8881280e89c0-0x00ff8881280e89c7]
CPU: 1 PID: 25615 Comm: syz.6.6812 Tainted: G    B   W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline]
RIP: 0010:atomic_read include/asm-generic/atomic-instrumented.h:28 [inline]
RIP: 0010:lock_page_memcg+0xb7/0x1c0 mm/memcontrol.c:2153
Code: 00 00 49 89 c6 4c 8d b8 c0 09 00 00 4c 89 ff be 04 00 00 00 e8 6a e3 fc ff 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 75 69 41 83 3f 00 0f 8e d1 00 00 00 4d 8d a6 d0
RSP: 0018:ffffc900014bed48 EFLAGS: 00010202
RAX: 001ff1102501d138 RBX: ffffea0004dd2ff8 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 00000000ffffffff
RBP: ffffc900014bed70 R08: 0000000000000004 R09: 0000000000000003
R10: fffffbfff0d8f048 R11: 1ffffffff0d8f048 R12: dffffc0000000000
R13: 1ffffd40009ba5ff R14: 00ff8881280e8000 R15: 00ff8881280e89c0
FS:  00007f1927c506c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f78d6e9fc00 CR3: 0000000153a8f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 page_add_file_rmap+0x2e/0x5d0 mm/rmap.c:1224
 do_set_pte+0x365/0x460 mm/memory.c:4196
 filemap_map_pages+0x5dd/0x1270 mm/filemap.c:3065
 do_fault_around mm/memory.c:4378 [inline]
 do_read_fault mm/memory.c:4393 [inline]
 do_fault mm/memory.c:4527 [inline]
 handle_pte_fault+0x1ae5/0x3750 mm/memory.c:4791
 __handle_mm_fault mm/memory.c:4944 [inline]
 handle_mm_fault+0xf3f/0x16a0 mm/memory.c:5358
 faultin_page mm/gup.c:902 [inline]
 __get_user_pages+0xbe9/0x13e0 mm/gup.c:1121
 __get_user_pages_locked mm/gup.c:1307 [inline]
 get_dump_page+0x169/0x5b0 mm/gup.c:1586
 dump_user_range+0x3c/0x1a0 fs/coredump.c:904
 elf_core_dump+0x278a/0x2bc0 fs/binfmt_elf.c:2290
 do_coredump+0x1ac9/0x27f0 fs/coredump.c:817
 get_signal+0xf23/0x12e0 kernel/signal.c:2779
 arch_do_signal_or_restart+0xbf/0x10f0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199
 irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:287
 irqentry_exit+0x12/0x60 kernel/entry/common.c:375
 exc_page_fault+0x67/0xc0 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
RIP: 0033:0x7f1929209751
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:00000000fffffe10 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f1929460090 RCX: 00007f1929209749
RDX: 0000000000000000 RSI: 00000000fffffe10 RDI: 0000000000000000
RBP: 00007f192928df91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1929460128 R14: 00007f1929460090 R15: 00007ffceef7c5f8
Modules linked in:
---[ end trace ade92f9e895eef38 ]---
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline]
RIP: 0010:atomic_read include/asm-generic/atomic-instrumented.h:28 [inline]
RIP: 0010:lock_page_memcg+0xb7/0x1c0 mm/memcontrol.c:2153
Code: 00 00 49 89 c6 4c 8d b8 c0 09 00 00 4c 89 ff be 04 00 00 00 e8 6a e3 fc ff 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 75 69 41 83 3f 00 0f 8e d1 00 00 00 4d 8d a6 d0
RSP: 0018:ffffc900014bed48 EFLAGS: 00010202
RAX: 001ff1102501d138 RBX: ffffea0004dd2ff8 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 00000000ffffffff
RBP: ffffc900014bed70 R08: 0000000000000004 R09: 0000000000000003
R10: fffffbfff0d8f048 R11: 1ffffffff0d8f048 R12: dffffc0000000000
R13: 1ffffd40009ba5ff R14: 00ff8881280e8000 R15: 00ff8881280e89c0
FS:  00007f1927c506c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f78d6e9fc00 CR3: 0000000153a8f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	49 89 c6             	mov    %rax,%r14
   5:	4c 8d b8 c0 09 00 00 	lea    0x9c0(%rax),%r15
   c:	4c 89 ff             	mov    %r15,%rdi
   f:	be 04 00 00 00       	mov    $0x4,%esi
  14:	e8 6a e3 fc ff       	call   0xfffce383
  19:	4c 89 f8             	mov    %r15,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	0f b6 04 08          	movzbl (%rax,%rcx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	75 69                	jne    0x9b
  32:	41 83 3f 00          	cmpl   $0x0,(%r15)
  36:	0f 8e d1 00 00 00    	jle    0x10d
  3c:	4d                   	rex.WRB
  3d:	8d                   	.byte 0x8d
  3e:	a6                   	cmpsb  %es:(%rdi),%ds:(%rsi)
  3f:	d0                   	.byte 0xd0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/10 12:37 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: wild-memory-access Read in page_add_file_rmap
* Struck through repros no longer work on HEAD.