================================================================== BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline] BUG: KASAN: use-after-free in tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596 Read of size 4 at addr ffff88802b40c810 by task syz-executor.0/371 CPU: 1 PID: 371 Comm: syz-executor.0 Not tainted 5.3.0-rc7+ #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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x17 mm/kasan/common.c:618 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline] tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596 tcp_write_timer+0xa8/0x1e0 net/ipv4/tcp_timer.c:612 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1133 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:mb_find_buddy+0x1c1/0x330 fs/ext4/mballoc.c:447 Code: 80 3c 02 00 0f 85 68 01 00 00 48 8b 83 20 04 00 00 4a 8d 1c a0 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 0f b6 14 02 <48> 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 3d 01 00 00 48 RSP: 0018:ffff88804ab372a0 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff888216636b18 RCX: ffffc90005f4d000 RDX: 0000000000000000 RSI: ffffffff81fa16f5 RDI: ffff888215e324e0 RBP: ffff88804ab372d0 R08: ffff888065fe2480 R09: ffffed10143cc5f5 R10: ffffed10143cc5f4 R11: ffff8880a1e62fa7 R12: 0000000000000006 R13: ffff88804ab37358 R14: ffff8880a1e62f80 R15: ffff88809b53f30c mb_find_extent+0x5b3/0x9c0 fs/ext4/mballoc.c:1527 ext4_mb_complex_scan_group+0x322/0x9d0 fs/ext4/mballoc.c:1961 ext4_mb_regular_allocator+0x939/0xff0 fs/ext4/mballoc.c:2216 ext4_mb_new_blocks+0x16d6/0x3870 fs/ext4/mballoc.c:4539 ext4_ext_map_blocks+0x2b34/0x5040 fs/ext4/extents.c:4414 ext4_map_blocks+0x529/0x17f0 fs/ext4/inode.c:640 ext4_alloc_file_blocks+0x29c/0xaf0 fs/ext4/extents.c:4603 ext4_fallocate+0x9a4/0x2470 fs/ext4/extents.c:4888 vfs_fallocate+0x4aa/0xa50 fs/open.c:309 ioctl_preallocate+0x197/0x210 fs/ioctl.c:490 file_ioctl fs/ioctl.c:506 [inline] do_vfs_ioctl+0x11c7/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459879 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f27b16fbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459879 RDX: 0000000020000000 RSI: 0000000040305828 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f27b16fc6d4 R13: 00000000004c2050 R14: 00000000004d5488 R15: 00000000ffffffff Allocated by task 15654: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:493 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:466 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:501 slab_post_alloc_hook mm/slab.h:520 [inline] slab_alloc mm/slab.c:3319 [inline] kmem_cache_alloc+0x121/0x710 mm/slab.c:3483 kmem_cache_zalloc include/linux/slab.h:738 [inline] net_alloc net/core/net_namespace.c:410 [inline] copy_net_ns+0xf1/0x41f net/core/net_namespace.c:462 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:103 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:202 ksys_unshare+0x444/0x980 kernel/fork.c:2831 __do_sys_unshare kernel/fork.c:2899 [inline] __se_sys_unshare kernel/fork.c:2897 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2897 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 2566: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:455 kasan_slab_free+0xe/0x10 mm/kasan/common.c:463 __cache_free mm/slab.c:3425 [inline] kmem_cache_free+0x86/0x320 mm/slab.c:3693 net_free net/core/net_namespace.c:438 [inline] net_drop_ns.part.0+0x70/0x90 net/core/net_namespace.c:445 net_drop_ns net/core/net_namespace.c:444 [inline] cleanup_net+0x774/0xa60 net/core/net_namespace.c:613 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 The buggy address belongs to the object at ffff88802b40c240 which belongs to the cache net_namespace of size 6784 The buggy address is located 1488 bytes inside of 6784-byte region [ffff88802b40c240, ffff88802b40dcc0) The buggy address belongs to the page: page:ffffea0000ad0300 refcount:1 mapcount:0 mapping:ffff88821b69e1c0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea00022cc688 ffffea0000f98988 ffff88821b69e1c0 raw: 0000000000000000 ffff88802b40c240 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88802b40c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b40c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802b40c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802b40c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b40c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================