================================================================== BUG: KASAN: slab-out-of-bounds in tcp_retransmit_timer+0x2d30/0x3220 net/ipv4/tcp_timer.c:500 Read of size 8 at addr ffff888061848290 by task syz-executor.1/6502 CPU: 1 PID: 6502 Comm: syz-executor.1 Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 tcp_retransmit_timer+0x2d30/0x3220 net/ipv4/tcp_timer.c:500 tcp_write_timer_handler+0x79b/0xa60 net/ipv4/tcp_timer.c:611 tcp_write_timer+0xa2/0x2b0 net/ipv4/tcp_timer.c:631 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1768 __do_softirq+0x2ed/0xab4 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x1f3/0x230 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:stack_trace_consume_entry+0xab/0x160 kernel/stacktrace.c:93 Code: c0 03 38 d0 7c 08 84 d2 0f 85 90 00 00 00 8b 43 0c 85 c0 75 53 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 80 3c 02 00 <0f> 85 92 00 00 00 8d 45 01 89 43 10 48 8b 03 48 8d 2c e8 48 b8 00 RSP: 0018:ffffc900058f7678 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffffc900058f7750 RCX: 0000000000000000 RDX: 1ffff92000b1eeea RSI: ffffffff81b777f7 RDI: ffffc900058f775c RBP: 0000000000000002 R08: ffffffff8ba99c02 R09: 0000000000000001 R10: 000000000007401e R11: 0000000000000001 R12: ffffc900058f7750 R13: 0000000000000000 R14: ffff88805f99e280 R15: 0000000000000080 arch_stack_walk+0x71/0xf0 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc_trace+0x137/0x310 mm/slab.c:3548 kmalloc include/linux/slab.h:554 [inline] iomap_dio_rw+0x1ec/0x1230 fs/iomap/direct-io.c:429 ext4_dio_write_iter fs/ext4/file.c:548 [inline] ext4_file_write_iter+0xe28/0x13f0 fs/ext4/file.c:658 call_write_iter include/linux/fs.h:1882 [inline] new_sync_write+0x422/0x650 fs/read_write.c:503 vfs_write+0x5ad/0x730 fs/read_write.c:578 ksys_write+0x12d/0x250 fs/read_write.c:631 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5f9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb11476ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000038f00 RCX: 000000000045d5f9 RDX: 0000000000248800 RSI: 0000000020000000 RDI: 0000000000000007 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffe9e72943f R14: 00007fb11476f9c0 R15: 000000000118cf4c Allocated by task 8969: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc_node mm/slab.c:3254 [inline] kmem_cache_alloc_node+0x136/0x440 mm/slab.c:3574 alloc_task_struct_node kernel/fork.c:169 [inline] dup_task_struct kernel/fork.c:858 [inline] copy_process+0x5d0/0x6a20 kernel/fork.c:1916 _do_fork+0xe8/0xb10 kernel/fork.c:2428 kernel_thread+0xb5/0xf0 kernel/fork.c:2480 call_usermodehelper_exec_work kernel/umh.c:163 [inline] call_usermodehelper_exec_work+0xcc/0x180 kernel/umh.c:149 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Freed by task 9: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 __put_task_struct+0x229/0x3b0 kernel/fork.c:739 put_task_struct include/linux/sched/task.h:113 [inline] delayed_put_task_struct+0x23a/0x3a0 kernel/exit.c:172 rcu_do_batch kernel/rcu/tree.c:2428 [inline] rcu_core+0x5c7/0x1190 kernel/rcu/tree.c:2656 __do_softirq+0x2ed/0xab4 kernel/softirq.c:298 Last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2894 [inline] call_rcu+0x14f/0x800 kernel/rcu/tree.c:2968 put_task_struct_rcu_user+0x7f/0xb0 kernel/exit.c:178 finish_task_switch+0x548/0x790 kernel/sched/core.c:3651 context_switch kernel/sched/core.c:3781 [inline] __schedule+0x904/0x2240 kernel/sched/core.c:4527 schedule_idle+0x53/0x90 kernel/sched/core.c:4630 do_idle+0x323/0x6d0 kernel/sched/idle.c:304 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:372 start_kernel+0x449/0x46a init/main.c:1048 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 The buggy address belongs to the object at ffff8880618482c0 which belongs to the cache task_struct of size 6464 The buggy address is located 48 bytes to the left of 6464-byte region [ffff8880618482c0, ffff888061849c00) The buggy address belongs to the page: page:000000000a7b4093 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61848 head:000000000a7b4093 order:1 compound_mapcount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea000134a208 ffffea000156b108 ffff88821bc47400 raw: 0000000000000000 ffff8880618482c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888061848180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888061848200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888061848280: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ^ ffff888061848300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888061848380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================