================================================================== 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 ffff888063f70790 by task syz-fuzzer/10037 CPU: 0 PID: 10037 Comm: syz-fuzzer Not tainted 5.3.0-rc8+ #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:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0033:0x7097e4 Code: 8d 51 01 48 8b 44 24 50 48 8b 5c 24 60 48 89 f1 48 39 c2 0f 8d 95 00 00 00 48 89 54 24 40 48 89 8c 24 e8 00 00 00 48 8b 41 08 <48> 8b 11 48 89 14 24 48 89 44 24 08 48 8b 84 24 10 01 00 00 48 89 RSP: 002b:000000c4267c4578 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: 000000c421c48960 RBX: 000000c428e2ba10 RCX: 000000c421c5e040 RDX: 0000000000000000 RSI: 0000000000000020 RDI: 0000000000001d58 RBP: 000000c4267c4668 R08: 0000000000000000 R09: 0000000000000038 R10: 00000000009c701e R11: 0000000000000004 R12: 00ffffffffffffff R13: 0000000000000001 R14: 00000000000000df R15: 0000000000000000 Allocated by task 3799: 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_kmalloc+0x9/0x10 mm/kasan/common.c:507 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x163/0x770 mm/slab.c:3664 kmalloc include/linux/slab.h:557 [inline] load_elf_phdrs+0x142/0x1f0 fs/binfmt_elf.c:437 load_elf_binary+0x9ee/0x5730 fs/binfmt_elf.c:836 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1333/0x2340 fs/exec.c:1821 do_execveat_common fs/exec.c:1868 [inline] do_execve fs/exec.c:1885 [inline] __do_sys_execve fs/exec.c:1961 [inline] __se_sys_execve fs/exec.c:1956 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1956 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 3799: 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] kfree+0x10a/0x2c0 mm/slab.c:3756 load_elf_binary+0x26bb/0x5730 fs/binfmt_elf.c:1115 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1333/0x2340 fs/exec.c:1821 do_execveat_common fs/exec.c:1868 [inline] do_execve fs/exec.c:1885 [inline] __do_sys_execve fs/exec.c:1961 [inline] __se_sys_execve fs/exec.c:1956 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1956 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888063f705c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 464 bytes inside of 512-byte region [ffff888063f705c0, ffff888063f707c0) The buggy address belongs to the page: page:ffffea00018fdc00 refcount:1 mapcount:0 mapping:ffff8880aa400a80 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00021ecdc8 ffffea00018d2f88 ffff8880aa400a80 raw: 0000000000000000 ffff888063f700c0 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888063f70680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888063f70700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888063f70780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff888063f70800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff888063f70880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================