================================================================== 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: 1 UID: 0 PID: 84 Comm: kswapd0 Not tainted 6.17.0-rc1-syzkaller-00224-g8d561baae505 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __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 ================================================================== Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] CPU: 1 UID: 0 PID: 84 Comm: kswapd0 Tainted: G B 6.17.0-rc1-syzkaller-00224-g8d561baae505 #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:ffffc9000212f0c0 EFLAGS: 00010216 RAX: 000000000000000c RBX: ffff888047c659b0 RCX: ffffffff817a460f RDX: ffff88801dfebc00 RSI: ffffffff8220c9a7 RDI: 0000000000000007 RBP: dffffc0000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 3d3d3d3d3d3d3d3d R12: 0000000000000060 R13: ffffea00027cda00 R14: 0000000000000000 R15: ffffea00027cda28 FS: 0000000000000000(0000) GS:ffff8881247bd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1a40fea000 CR3: 0000000023ed2000 CR4: 0000000000350ef0 Call Trace: 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 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