syzbot

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: null-ptr-deref in buffer_busy fs/buffer.c:2886 [inline]
BUG: KASAN: null-ptr-deref in drop_buffers.constprop.0+0x89/0x340 fs/buffer.c:2898
Read of size 4 at addr 0000000000000060 by task kswapd0/84

CPU: 0 UID: 0 PID: 84 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 buffer_busy fs/buffer.c:2886 [inline]
 drop_buffers.constprop.0+0x89/0x340 fs/buffer.c:2898
 try_to_free_buffers+0x21c/0x2d0 fs/buffer.c:2952
 filemap_release_folio+0x219/0x280 mm/filemap.c:4356
 shrink_folio_list+0x28a9/0x4880 mm/vmscan.c:1518
 evict_folios+0x79c/0x1b30 mm/vmscan.c:4744
 try_to_shrink_lruvec+0x585/0x9b0 mm/vmscan.c:4907
 shrink_one+0x3e3/0x7a0 mm/vmscan.c:4952
 shrink_many mm/vmscan.c:5015 [inline]
 lru_gen_shrink_node mm/vmscan.c:5093 [inline]
 shrink_node+0x26b5/0x3d50 mm/vmscan.c:6078
 kswapd_shrink_node mm/vmscan.c:6938 [inline]
 balance_pgdat+0xbb8/0x1a70 mm/vmscan.c:7121
 kswapd+0x590/0xb90 mm/vmscan.c:7386
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
==================================================================
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 0 UID: 0 PID: 84 Comm: kswapd0 Tainted: G    B               syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:buffer_busy fs/buffer.c:2886 [inline]
RIP: 0010:drop_buffers.constprop.0+0x90/0x340 fs/buffer.c:2898
Code: 4d 8b 76 08 4c 39 f3 0f 84 84 00 00 00 e8 08 af 74 ff 4d 8d 66 60 be 04 00 00 00 4c 89 e7 e8 67 17 da ff 4c 89 e0 48 c1 e8 03 <0f> b6 0c 28 4c 89 e0 83 e0 07 83 c0 03 38 c8 7c 08 84 c9 0f 85 2d
RSP: 0018:ffffc9000213f0c0 EFLAGS: 00010216
RAX: 000000000000000c RBX: ffff88801249eba0 RCX: ffffffff817a460f
RDX: ffff88801e343c00 RSI: ffffffff8220c8f7 RDI: 0000000000000007
RBP: dffffc0000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 3d3d3d3d3d3d3d3d R12: 0000000000000060
R13: ffffea000152b040 R14: 0000000000000000 R15: ffffea000152b068
FS:  0000000000000000(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd13ae17dc CR3: 0000000075ac4000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 try_to_free_buffers+0x21c/0x2d0 fs/buffer.c:2952
 filemap_release_folio+0x219/0x280 mm/filemap.c:4356
 shrink_folio_list+0x28a9/0x4880 mm/vmscan.c:1518
 evict_folios+0x79c/0x1b30 mm/vmscan.c:4744
 try_to_shrink_lruvec+0x585/0x9b0 mm/vmscan.c:4907
 shrink_one+0x3e3/0x7a0 mm/vmscan.c:4952
 shrink_many mm/vmscan.c:5015 [inline]
 lru_gen_shrink_node mm/vmscan.c:5093 [inline]
 shrink_node+0x26b5/0x3d50 mm/vmscan.c:6078
 kswapd_shrink_node mm/vmscan.c:6938 [inline]
 balance_pgdat+0xbb8/0x1a70 mm/vmscan.c:7121
 kswapd+0x590/0xb90 mm/vmscan.c:7386
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	4d 8b 76 08          	mov    0x8(%r14),%r14
   4:	4c 39 f3             	cmp    %r14,%rbx
   7:	0f 84 84 00 00 00    	je     0x91
   d:	e8 08 af 74 ff       	call   0xff74af1a
  12:	4d 8d 66 60          	lea    0x60(%r14),%r12
  16:	be 04 00 00 00       	mov    $0x4,%esi
  1b:	4c 89 e7             	mov    %r12,%rdi
  1e:	e8 67 17 da ff       	call   0xffda178a
  23:	4c 89 e0             	mov    %r12,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	0f b6 0c 28          	movzbl (%rax,%rbp,1),%ecx <-- trapping instruction
  2e:	4c 89 e0             	mov    %r12,%rax
  31:	83 e0 07             	and    $0x7,%eax
  34:	83 c0 03             	add    $0x3,%eax
  37:	38 c8                	cmp    %cl,%al
  39:	7c 08                	jl     0x43
  3b:	84 c9                	test   %cl,%cl
  3d:	0f                   	.byte 0xf
  3e:	85                   	.byte 0x85
  3f:	2d                   	.byte 0x2d