================================================================== BUG: KASAN: out-of-bounds in instrument_atomic_read_write include/linux/instrumented.h:96 [inline] BUG: KASAN: out-of-bounds in atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline] BUG: KASAN: out-of-bounds in put_bh include/linux/buffer_head.h:308 [inline] BUG: KASAN: out-of-bounds in end_buffer_read_sync+0xc3/0xd0 fs/buffer.c:161 Write of size 4 at addr ffffc90003baf740 by task kworker/u4:7/3394 CPU: 0 PID: 3394 Comm: kworker/u4:7 Not tainted 6.6.93-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: loop0 loop_workfn Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xac/0x230 mm/kasan/report.c:475 kasan_report+0x151/0x180 mm/kasan/report.c:588 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x288/0x290 mm/kasan/generic.c:187 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline] put_bh include/linux/buffer_head.h:308 [inline] end_buffer_read_sync+0xc3/0xd0 fs/buffer.c:161 end_bio_bh_io_sync+0xb7/0x110 fs/buffer.c:2784 req_bio_endio block/blk-mq.c:784 [inline] blk_update_request+0x597/0xe40 block/blk-mq.c:929 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1056 blk_complete_reqs block/blk-mq.c:1136 [inline] blk_done_softirq+0x10b/0x160 block/blk-mq.c:1141 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_call_function_single arch/x86/kernel/smp.c:262 [inline] sysvec_call_function_single+0xa1/0xc0 arch/x86/kernel/smp.c:262 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:694 RIP: 0010:raise_softirq+0xfd/0x150 kernel/softirq.c:718 Code: 68 3a 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 45 41 f7 c7 00 02 00 00 74 01 fb 48 c7 04 24 0e 36 e0 45 <4a> c7 04 33 00 00 00 00 66 42 c7 44 33 09 00 00 42 c6 44 33 0b 00 RSP: 0018:ffffc9000c737820 EFLAGS: 00000206 RAX: a5ff141784124700 RBX: 1ffff920018e6f04 RCX: a5ff141784124700 RDX: dffffc0000000000 RSI: ffffffff8aaab2c0 RDI: ffffffff8afc6780 RBP: ffffc9000c7378d0 R08: ffffffff90d84627 R09: 1ffffffff21b08c4 R10: dffffc0000000000 R11: fffffbfff21b08c5 R12: 0000000000000004 R13: 1ffff1100439d2c0 R14: dffffc0000000000 R15: 0000000000000a02 blk_mq_raise_softirq block/blk-mq.c:1197 [inline] blk_mq_complete_request_remote+0x4e1/0x6c0 block/blk-mq.c:1221 blk_mq_complete_request+0x19/0xa0 block/blk-mq.c:1237 loop_handle_cmd drivers/block/loop.c:1928 [inline] loop_process_work+0x185b/0x1ed0 drivers/block/loop.c:1946 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 The buggy address belongs to the virtual mapping at [ffffc90003ba8000, ffffc90003bb1000) created by: copy_process+0x549/0x3d70 kernel/fork.c:2331 The buggy address belongs to the physical page: page:ffffea000183d180 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x60f46 memcg:ffff88814a6ee602 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff ffff88814a6ee602 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 11505, tgid 11505 (syz.0.1299), ts 853856533129, free_ts 852663332925 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554 prep_new_page mm/page_alloc.c:1561 [inline] get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457 vm_area_alloc_pages mm/vmalloc.c:3081 [inline] __vmalloc_area_node mm/vmalloc.c:3150 [inline] __vmalloc_node_range+0x96b/0x1320 mm/vmalloc.c:3331 alloc_thread_stack_node kernel/fork.c:310 [inline] dup_task_struct+0x3d0/0x7c0 kernel/fork.c:1124 copy_process+0x549/0x3d70 kernel/fork.c:2331 kernel_clone+0x21b/0x840 kernel/fork.c:2914 __do_sys_clone3 kernel/fork.c:3215 [inline] __se_sys_clone3+0x252/0x2c0 kernel/fork.c:3199 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1154 [inline] free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475 release_pages+0x1fa0/0x2220 mm/swap.c:1022 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline] tlb_flush_mmu_free mm/mmu_gather.c:293 [inline] tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300 zap_pte_range mm/memory.c:1531 [inline] zap_pmd_range mm/memory.c:1570 [inline] zap_pud_range mm/memory.c:1599 [inline] zap_p4d_range mm/memory.c:1620 [inline] unmap_page_range+0x26d4/0x2fe0 mm/memory.c:1641 unmap_vmas+0x25e/0x3a0 mm/memory.c:1731 exit_mmap+0x200/0xb50 mm/mmap.c:3292 __mmput+0x118/0x3c0 kernel/fork.c:1355 exit_mm+0x1da/0x2c0 kernel/exit.c:569 do_exit+0x886/0x23c0 kernel/exit.c:861 do_group_exit+0x21b/0x2d0 kernel/exit.c:1023 __do_sys_exit_group kernel/exit.c:1034 [inline] __se_sys_exit_group kernel/exit.c:1032 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1032 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Memory state around the buggy address: ffffc90003baf600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90003baf680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc90003baf700: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 f2 ^ ffffc90003baf780: f2 f2 f2 f2 00 f2 f2 f2 01 f3 f3 f3 00 00 00 00 ffffc90003baf800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== ---------------- Code disassembly (best guess): 0: 68 3a 00 48 c7 push $0xffffffffc748003a 5: 44 24 20 rex.R and $0x20,%al 8: 00 00 add %al,(%rax) a: 00 00 add %al,(%rax) c: 9c pushf d: 8f 44 24 20 pop 0x20(%rsp) 11: f6 44 24 21 02 testb $0x2,0x21(%rsp) 16: 75 45 jne 0x5d 18: 41 f7 c7 00 02 00 00 test $0x200,%r15d 1f: 74 01 je 0x22 21: fb sti 22: 48 c7 04 24 0e 36 e0 movq $0x45e0360e,(%rsp) 29: 45 * 2a: 4a c7 04 33 00 00 00 movq $0x0,(%rbx,%r14,1) <-- trapping instruction 31: 00 32: 66 42 c7 44 33 09 00 movw $0x0,0x9(%rbx,%r14,1) 39: 00 3a: 42 c6 44 33 0b 00 movb $0x0,0xb(%rbx,%r14,1)