================================================================== BUG: KASAN: stack-out-of-bounds in profile_pc+0x186/0x1a0 arch/x86/kernel/time.c:44 Read of size 8 at addr ffffc9000403f888 by task syz.2.544/6698 CPU: 1 PID: 6698 Comm: syz.2.544 Not tainted 6.10.0-rc5-syzkaller-00155-g66e55ff12e73 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 profile_pc+0x186/0x1a0 arch/x86/kernel/time.c:44 profile_tick+0xd3/0x140 kernel/profile.c:339 tick_sched_handle kernel/time/tick-sched.c:277 [inline] tick_nohz_handler+0x380/0x530 kernel/time/tick-sched.c:297 __run_hrtimer kernel/time/hrtimer.c:1687 [inline] __hrtimer_run_queues+0x657/0xcc0 kernel/time/hrtimer.c:1751 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1813 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x10f/0x450 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:queued_read_lock_slowpath+0x131/0x2b1 kernel/locking/qrwlock.c:51 Code: 85 45 01 00 00 8b 03 84 c0 74 36 48 b8 00 00 00 00 00 fc ff df 49 89 de 48 89 dd 49 c1 ee 03 83 e5 07 49 01 c6 83 c5 03 f3 90 <41> 0f b6 06 40 38 c5 7c 08 84 c0 0f 85 1f 01 00 00 8b 03 84 c0 75 RSP: 0000:ffffc9000403f880 EFLAGS: 00000286 RAX: 00000000000002ff RBX: ffff88801eb080b0 RCX: ffffffff8adff3cb RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88801eb080b0 RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed1003d61016 R10: ffff88801eb080b3 R11: 0000000000000002 R12: 1ffff92000807f11 R13: ffff88801eb080b4 R14: ffffed1003d61016 R15: ffff88801eb08000 start_this_handle+0x249/0x15e0 fs/jbd2/transaction.c:383 jbd2__journal_start+0x394/0x6a0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x358/0x660 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:5932 __mark_inode_dirty+0x1f0/0xe70 fs/fs-writeback.c:2486 generic_update_time+0xcf/0xf0 fs/inode.c:1907 inode_update_time fs/inode.c:1920 [inline] __file_update_time fs/inode.c:2109 [inline] file_update_time+0x137/0x170 fs/inode.c:2139 ext4_page_mkwrite+0x36e/0x1760 fs/ext4/inode.c:6053 do_page_mkwrite+0x17d/0x390 mm/memory.c:3093 do_shared_fault mm/memory.c:4993 [inline] do_fault mm/memory.c:5055 [inline] do_pte_missing mm/memory.c:3897 [inline] handle_pte_fault mm/memory.c:5381 [inline] __handle_mm_fault+0x3b99/0x52a0 mm/memory.c:5524 handle_mm_fault+0x476/0xa00 mm/memory.c:5689 do_user_addr_fault+0x426/0xe50 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0023:0xf71ceca7 Code: 00 00 00 e8 5b b2 fe ff 8b 44 24 50 8b 5c 24 50 8b 4c 24 10 83 44 24 20 01 8b 40 1c 83 43 14 08 8d 50 f8 89 53 1c 8b 5c 24 14 <89> 48 f8 89 58 fc e9 de fe ff ff 8d b6 00 00 00 00 8b 44 24 50 89 RSP: 002b:00000000fff19dc0 EFLAGS: 00010202 RAX: 00000000313fd000 RBX: 00000000ffffffff RCX: 000000008614fd6a RDX: 00000000313fcff8 RSI: 000000008614ff01 RDI: 00000000ffffffff RBP: 00000000f749f008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to stack of task syz.2.544/6698 and is located at offset 0 in frame: queued_read_lock_slowpath+0x0/0x2b1 This frame has 1 object: [32, 36) 'val' The buggy address belongs to the virtual mapping at [ffffc90004038000, ffffc90004041000) created by: vhost_task_create+0x1bd/0x2b0 kernel/vhost_task.c:145 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888055c701e0 pfn:0x55c70 memcg:ffff88802665cc82 flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff) raw: 04fff00000000000 0000000000000000 dead000000000122 0000000000000000 raw: ffff888055c701e0 0000000000000000 00000001ffffffff ffff88802665cc82 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 6582, tgid 6572 (syz.0.491), ts 98996560846, free_ts 98892996830 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1473 prep_new_page mm/page_alloc.c:1481 [inline] get_page_from_freelist+0x1353/0x2e50 mm/page_alloc.c:3425 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4683 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2265 vm_area_alloc_pages mm/vmalloc.c:3575 [inline] __vmalloc_area_node mm/vmalloc.c:3651 [inline] __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3832 alloc_thread_stack_node kernel/fork.c:309 [inline] dup_task_struct kernel/fork.c:1115 [inline] copy_process+0x29f5/0x6f50 kernel/fork.c:2220 vhost_task_create+0x1bd/0x2b0 kernel/vhost_task.c:145 vhost_worker_create+0x152/0x370 drivers/vhost/vhost.c:667 vhost_dev_set_owner+0x5c8/0xa70 drivers/vhost/vhost.c:945 vhost_net_set_owner drivers/vhost/net.c:1657 [inline] vhost_net_ioctl+0x696/0x16f0 drivers/vhost/net.c:1707 compat_ptr_ioctl+0x71/0xb0 fs/ioctl.c:946 __do_compat_sys_ioctl+0x2c3/0x330 fs/ioctl.c:1007 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e page last free pid 29 tgid 29 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1093 [inline] free_unref_page+0x64a/0xe40 mm/page_alloc.c:2588 __folio_put+0x239/0x360 mm/swap.c:129 folio_put include/linux/mm.h:1513 [inline] free_page_and_swap_cache+0x249/0x2c0 mm/swap_state.c:305 __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline] __tlb_remove_table_free mm/mmu_gather.c:227 [inline] tlb_remove_table_rcu+0x89/0xe0 mm/mmu_gather.c:282 rcu_do_batch kernel/rcu/tree.c:2535 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2809 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554 run_ksoftirqd kernel/softirq.c:928 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:920 smpboot_thread_fn+0x661/0xa10 kernel/smpboot.c:164 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Memory state around the buggy address: ffffc9000403f780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc9000403f800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc9000403f880: 00 f1 f1 f1 f1 04 f3 f3 f3 00 00 00 00 00 00 00 ^ ffffc9000403f900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc9000403f980: 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 f3 f3 f3 f3 ================================================================== ---------------- Code disassembly (best guess): 0: 85 45 01 test %eax,0x1(%rbp) 3: 00 00 add %al,(%rax) 5: 8b 03 mov (%rbx),%eax 7: 84 c0 test %al,%al 9: 74 36 je 0x41 b: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 12: fc ff df 15: 49 89 de mov %rbx,%r14 18: 48 89 dd mov %rbx,%rbp 1b: 49 c1 ee 03 shr $0x3,%r14 1f: 83 e5 07 and $0x7,%ebp 22: 49 01 c6 add %rax,%r14 25: 83 c5 03 add $0x3,%ebp 28: f3 90 pause * 2a: 41 0f b6 06 movzbl (%r14),%eax <-- trapping instruction 2e: 40 38 c5 cmp %al,%bpl 31: 7c 08 jl 0x3b 33: 84 c0 test %al,%al 35: 0f 85 1f 01 00 00 jne 0x15a 3b: 8b 03 mov (%rbx),%eax 3d: 84 c0 test %al,%al 3f: 75 .byte 0x75