syzbot has found a reproducer for the following issue on: HEAD commit: 819d11507f66 bpf, selftests: Fix spelling mistake "tained".. git tree: bpf console output: https://syzkaller.appspot.com/x/log.txt?x=138bf80db00000 kernel config: https://syzkaller.appspot.com/x/.config?x=22b66456935ee10 dashboard link: https://syzkaller.appspot.com/bug?extid=694120e1002c117747ed compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=172ccbcdb00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14fcccedb00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+694120e1002c117747ed@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x2ea2/0x3320 net/ipv4/tcp_timer.c:511 Read of size 8 at addr ffff888075d9b6d8 by task jbd2/sda1-8/2936 CPU: 1 PID: 2936 Comm: jbd2/sda1-8 Not tainted 5.16.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247 __kasan_report mm/kasan/report.c:433 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 tcp_retransmit_timer+0x2ea2/0x3320 net/ipv4/tcp_timer.c:511 tcp_write_timer_handler+0x5e6/0xbc0 net/ipv4/tcp_timer.c:622 tcp_write_timer+0xa2/0x2b0 net/ipv4/tcp_timer.c:642 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1c/0x60 kernel/kcov.c:200 Code: be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 8b 05 29 be 8a 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 40 70 02 00 <a9> 00 01 ff 00 74 0e 85 c9 74 35 8b 82 a4 15 00 00 85 c0 74 2b 8b RSP: 0018:ffffc9000cc8f7e0 EFLAGS: 00000246 RAX: 0000000080000001 RBX: 0000000000005460 RCX: 0000000000000000 RDX: ffff88807dcdd700 RSI: ffffffff82149a29 RDI: 0000000000000003 RBP: 0000000000008000 R08: 0000000000008000 R09: ffff88801d0598ff R10: ffffffff82149a1c R11: 0000000000000000 R12: ffff88801d059a88 R13: 00000000ffffffff R14: ffff88801d059000 R15: 00000000ffffffff mb_test_and_clear_bits+0xd9/0x240 fs/ext4/mballoc.c:1675 mb_free_blocks+0x364/0x1370 fs/ext4/mballoc.c:1811 ext4_free_data_in_buddy fs/ext4/mballoc.c:3662 [inline] ext4_process_freed_data+0x56c/0x1070 fs/ext4/mballoc.c:3713 ext4_journal_commit_callback+0x11e/0x380 fs/ext4/super.c:449 jbd2_journal_commit_transaction+0x55a8/0x6be0 fs/jbd2/commit.c:1171 kjournald2+0x1d0/0x930 fs/jbd2/journal.c:213 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> Allocated by task 3696: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3234 [inline] slab_alloc mm/slub.c:3242 [inline] kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3247 kmem_cache_zalloc include/linux/slab.h:714 [inline] net_alloc net/core/net_namespace.c:402 [inline] copy_net_ns+0x125/0x760 net/core/net_namespace.c:457 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3075 __do_sys_unshare kernel/fork.c:3146 [inline] __se_sys_unshare kernel/fork.c:3144 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3144 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 503: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749 slab_free mm/slub.c:3513 [inline] kmem_cache_free+0xbd/0x5d0 mm/slub.c:3530 net_free net/core/net_namespace.c:431 [inline] net_free net/core/net_namespace.c:427 [inline] cleanup_net+0x8ba/0xb00 net/core/net_namespace.c:614 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff888075d9b480 which belongs to the cache net_namespace of size 6464 The buggy address is located 600 bytes inside of 6464-byte region [ffff888075d9b480, ffff888075d9cdc0) The buggy address belongs to the page: page:ffffea0001d76600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75d98 head:ffffea0001d76600 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011885000 raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3693, ts 1611631437660, free_ts 92175173930 prep_new_page mm/page_alloc.c:2418 [inline] get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4149 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2191 alloc_slab_page mm/slub.c:1793 [inline] allocate_slab mm/slub.c:1930 [inline] new_slab+0x32d/0x4a0 mm/slub.c:1993 ___slab_alloc+0x918/0xfe0 mm/slub.c:3022 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3109 slab_alloc_node mm/slub.c:3200 [inline] slab_alloc mm/slub.c:3242 [inline] kmem_cache_alloc+0x35c/0x3a0 mm/slub.c:3247 kmem_cache_zalloc include/linux/slab.h:714 [inline] net_alloc net/core/net_namespace.c:402 [inline] copy_net_ns+0x125/0x760 net/core/net_namespace.c:457 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3075 __do_sys_unshare kernel/fork.c:3146 [inline] __se_sys_unshare kernel/fork.c:3144 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3144 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1338 [inline] free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1389 free_unref_page_prepare mm/page_alloc.c:3309 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3388 __unfreeze_partials+0x343/0x360 mm/slub.c:2527 qlink_free mm/kasan/quarantine.c:146 [inline] qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3234 [inline] kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3270 __alloc_skb+0x215/0x340 net/core/skbuff.c:414 alloc_skb include/linux/skbuff.h:1126 [inline] alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:6078 sock_alloc_send_pskb+0x783/0x910 net/core/sock.c:2575 unix_dgram_sendmsg+0x3ec/0x1950 net/unix/af_unix.c:1811 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 sock_write_iter+0x289/0x3c0 net/socket.c:1057 call_write_iter include/linux/fs.h:2162 [inline] new_sync_write+0x429/0x660 fs/read_write.c:503 vfs_write+0x7cd/0xae0 fs/read_write.c:590 ksys_write+0x1ee/0x250 fs/read_write.c:643 Memory state around the buggy address: ffff888075d9b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888075d9b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888075d9b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888075d9b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888075d9b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: be b0 01 00 00 mov $0x1b0,%esi 5: e8 b4 ff ff ff callq 0xffffffbe a: 31 c0 xor %eax,%eax c: c3 retq d: 90 nop e: 65 8b 05 29 be 8a 7e mov %gs:0x7e8abe29(%rip),%eax # 0x7e8abe3e 15: 89 c1 mov %eax,%ecx 17: 48 8b 34 24 mov (%rsp),%rsi 1b: 81 e1 00 01 00 00 and $0x100,%ecx 21: 65 48 8b 14 25 40 70 mov %gs:0x27040,%rdx 28: 02 00 * 2a: a9 00 01 ff 00 test $0xff0100,%eax <-- trapping instruction 2f: 74 0e je 0x3f 31: 85 c9 test %ecx,%ecx 33: 74 35 je 0x6a 35: 8b 82 a4 15 00 00 mov 0x15a4(%rdx),%eax 3b: 85 c0 test %eax,%eax 3d: 74 2b je 0x6a 3f: 8b .byte 0x8b
