From: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Fri, 22 Sep 2023 05:20:34 +0200 > On Fri, Sep 22, 2023 at 1:15 AM Dmitry Safonov <dima@xxxxxxxxxx> wrote: > > > > Hi Eric, > > > > On 9/21/23 18:01, Dmitry Safonov wrote: > > > On 9/21/23 17:59, Eric Dumazet wrote: > > >> On Thu, Sep 21, 2023 at 6:56 PM syzbot > > >> <syzbot+68662811b3d5f6695bcb@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > >>> > > >>> Hello, > > >>> > > >>> syzbot found the following issue on: > > >>> > > >>> HEAD commit: ee3f96b16468 Merge tag 'nfsd-6.3-1' of git://git.kernel.or.. > > >>> git tree: upstream > > >>> console output: https://syzkaller.appspot.com/x/log.txt?x=1312bba8c80000 > > >>> kernel config: https://syzkaller.appspot.com/x/.config?x=f5733ca1757172ad > > >>> dashboard link: https://syzkaller.appspot.com/bug?extid=68662811b3d5f6695bcb > > >>> 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=105393a8c80000 > > >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1113917f480000 > > >>> > > >>> Downloadable assets: > > >>> disk image: https://storage.googleapis.com/syzbot-assets/29e7966ab711/disk-ee3f96b1.raw.xz > > >>> vmlinux: https://storage.googleapis.com/syzbot-assets/ae21b8e855de/vmlinux-ee3f96b1.xz > > >>> kernel image: https://storage.googleapis.com/syzbot-assets/803ee0425ad6/bzImage-ee3f96b1.xz > > >>> > > >>> IMPORTANT: if you fix the issue, please add the following tag to the commit: > > >>> Reported-by: syzbot+68662811b3d5f6695bcb@xxxxxxxxxxxxxxxxxxxxxxxxx > > >>> > > >>> executing program > > >>> BUG: memory leak > > >>> unreferenced object 0xffff88810a86f7a0 (size 32): > > >>> comm "syz-executor325", pid 5099, jiffies 4294978342 (age 119.240s) > > >>> hex dump (first 32 bytes): > > >>> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > > >>> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > > >>> backtrace: > > >>> [<ffffffff81533d64>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1061 > > >>> [<ffffffff840edaa0>] kmalloc include/linux/slab.h:580 [inline] > > >>> [<ffffffff840edaa0>] tcp_md5sig_info_add net/ipv4/tcp_ipv4.c:1169 [inline] > > >>> [<ffffffff840edaa0>] tcp_md5_do_add+0xa0/0x150 net/ipv4/tcp_ipv4.c:1240 > > >>> [<ffffffff84262c73>] tcp_v6_parse_md5_keys+0x253/0x4a0 net/ipv6/tcp_ipv6.c:671 > > >>> [<ffffffff840c720e>] do_tcp_setsockopt+0x40e/0x1360 net/ipv4/tcp.c:3720 > > >>> [<ffffffff840c81fb>] tcp_setsockopt+0x9b/0xa0 net/ipv4/tcp.c:3806 > > >>> [<ffffffff83d72a8b>] __sys_setsockopt+0x1ab/0x330 net/socket.c:2274 > > >>> [<ffffffff83d72c36>] __do_sys_setsockopt net/socket.c:2285 [inline] > > >>> [<ffffffff83d72c36>] __se_sys_setsockopt net/socket.c:2282 [inline] > > >>> [<ffffffff83d72c36>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2282 > > >>> [<ffffffff849ad699>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > >>> [<ffffffff849ad699>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > > >>> [<ffffffff84a0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > >>> > > >>> BUG: memory leak > > >>> unreferenced object 0xffff88811225ccc0 (size 192): > > >>> comm "syz-executor325", pid 5099, jiffies 4294978342 (age 119.240s) > > >>> hex dump (first 32 bytes): > > >>> 00 00 00 00 00 00 00 00 22 01 00 00 00 00 ad de ........"....... > > >>> 22 0a 80 00 fe 80 00 00 00 00 00 00 00 00 00 00 "............... > > >>> backtrace: > > >>> [<ffffffff8153444a>] __do_kmalloc_node mm/slab_common.c:966 [inline] > > >>> [<ffffffff8153444a>] __kmalloc+0x4a/0x120 mm/slab_common.c:980 > > >>> [<ffffffff83d75c15>] kmalloc include/linux/slab.h:584 [inline] > > >>> [<ffffffff83d75c15>] sock_kmalloc net/core/sock.c:2635 [inline] > > >>> [<ffffffff83d75c15>] sock_kmalloc+0x65/0xa0 net/core/sock.c:2624 > > >>> [<ffffffff840eb9bb>] __tcp_md5_do_add+0xcb/0x300 net/ipv4/tcp_ipv4.c:1212 > > >>> [<ffffffff840eda67>] tcp_md5_do_add+0x67/0x150 net/ipv4/tcp_ipv4.c:1253 > > >>> [<ffffffff84262c73>] tcp_v6_parse_md5_keys+0x253/0x4a0 net/ipv6/tcp_ipv6.c:671 > > >>> [<ffffffff840c720e>] do_tcp_setsockopt+0x40e/0x1360 net/ipv4/tcp.c:3720 > > >>> [<ffffffff840c81fb>] tcp_setsockopt+0x9b/0xa0 net/ipv4/tcp.c:3806 > > >>> [<ffffffff83d72a8b>] __sys_setsockopt+0x1ab/0x330 net/socket.c:2274 > > >>> [<ffffffff83d72c36>] __do_sys_setsockopt net/socket.c:2285 [inline] > > >>> [<ffffffff83d72c36>] __se_sys_setsockopt net/socket.c:2282 [inline] > > >>> [<ffffffff83d72c36>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2282 > > >>> [<ffffffff849ad699>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > >>> [<ffffffff849ad699>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > > >>> [<ffffffff84a0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > >>> > > >>> > > >>> > > >>> --- > > >>> This report is generated by a bot. It may contain errors. > > >>> See https://goo.gl/tpsmEJ for more information about syzbot. > > >>> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > >>> > > >>> syzbot will keep track of this issue. See: > > >>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > >>> > > >>> If the bug is already fixed, let syzbot know by replying with: > > >>> #syz fix: exact-commit-title > > >>> > > >>> If you want syzbot to run the reproducer, reply with: > > >>> #syz test: git://repo/address.git branch-or-commit-hash > > >>> If you attach or paste a git patch, syzbot will apply it before testing. > > >>> > > >>> If you want to overwrite bug's subsystems, reply with: > > >>> #syz set subsystems: new-subsystem > > >>> (See the list of subsystem names on the web dashboard) > > >>> > > >>> If the bug is a duplicate of another bug, reply with: > > >>> #syz dup: exact-subject-of-another-report > > >>> > > >>> If you want to undo deduplication, reply with: > > >>> #syz undup > > >> > > >> Dmitry, please take a look at this bug, we need to fix it before your > > >> patch series. > > > > > > Sure, seems reasonable to me to fix before merging something on top. > > > > It seems to me that it's related to a race between RCU grace period and > > kmemleak scan period. There seems to be a patch [1] that likely fixes > > that, albeit I couldn't verify it as all my attempts to reproduce syzbot > > issue produced only unrelated to TCP-MD5 log: > > > > I doubt this, looking at the repro, which seems to abuse a not often > used feature of TCP (self connect) > > # https://syzkaller.appspot.com/bug?id=323165b5fe193114de7a3a6a8bd16cf3a3c36ecf > # See https://goo.gl/kgGztJ for information about syzkaller reproducers. > #{"repeat":true,"procs":1,"slowdown":1,"sandbox":"none","sandbox_arg":0,"leak":true,"netdev":true,"close_fds":true,"usb":true} > r0 = socket$inet6_tcp(0xa, 0x1, 0x0) > setsockopt$inet6_tcp_TCP_MD5SIG(r0, 0x6, 0xe, > &(0x7f0000000040)={@in6={{0xa, 0x0, 0x0, @local}}, 0x0, 0x0, 0x22, > 0x0, "b05423587c18814d6b1a5f25671d09815a4687d637ffc958defc671aad3d4de8ac7d88560c759d600ab650c07ef0ef162b199da0d017fe6f0ae40cfb4e241cf9a990f20f6b8c2c070a61cfad8a2d2600"}, > 0xd8) > connect$inet6(r0, &(0x7f0000000180)={0xa, 0x4001, 0x0, @ipv4={'\x00', > '\xff\xff', @remote}}, 0x1c) > dup(0xffffffffffffffff) > setsockopt$SO_BINDTODEVICE(r0, 0x1, 0x19, > &(0x7f00000001c0)='ip6_vti0\x00', 0xff4a) FWIW, I had the same report and another report for twsk and MD5. syzkaller did not find repro though. ---8<--- BUG: memory leak unreferenced object 0xffff888038513480 (size 192): comm "syz-executor.0", pid 36537, jiffies 4295853096 (age 63.376s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 3e fc 43 80 88 ff ff .........>.C.... 06 02 20 00 ac 14 14 aa 00 00 00 00 00 00 00 00 .. ............. backtrace: [<0000000003e890c3>] __do_kmalloc_node mm/slab_common.c:984 [inline] [<0000000003e890c3>] __kmalloc_node_track_caller+0x4b/0x130 mm/slab_common.c:1005 [<0000000026777435>] kmemdup+0x2c/0x60 mm/util.c:131 [<000000000318308e>] kmemdup include/linux/fortify-string.h:765 [inline] [<000000000318308e>] tcp_time_wait_init net/ipv4/tcp_minisocks.c:261 [inline] [<000000000318308e>] tcp_time_wait+0x25c/0x3b0 net/ipv4/tcp_minisocks.c:318 [<00000000bb86ba54>] tcp_rcv_state_process+0xb36/0x1990 net/ipv4/tcp_input.c:6668 [<00000000a26563d5>] tcp_v4_do_rcv+0x18b/0x4a0 net/ipv4/tcp_ipv4.c:1751 [<00000000b158e1f0>] sk_backlog_rcv include/net/sock.h:1115 [inline] [<00000000b158e1f0>] __release_sock+0x177/0x1a0 net/core/sock.c:2982 [<000000000e8687d8>] __tcp_close+0x252/0x630 net/ipv4/tcp.c:2846 [<000000006b8a2f7d>] tcp_close+0x2d/0xc0 net/ipv4/tcp.c:2922 [<00000000d4c1915c>] inet_release+0x82/0xf0 net/ipv4/af_inet.c:433 [<00000000590c8ed6>] __sock_release+0x4b/0xf0 net/socket.c:657 [<00000000d49971a8>] sock_close+0x19/0x30 net/socket.c:1399 [<0000000097cacf4d>] __fput+0x1d0/0x4b0 fs/file_table.c:384 [<000000006a98802f>] __fput_sync+0x37/0x40 fs/file_table.c:465 [<00000000a6ebd3a7>] __do_sys_close fs/open.c:1572 [inline] [<00000000a6ebd3a7>] __se_sys_close fs/open.c:1557 [inline] [<00000000a6ebd3a7>] __x64_sys_close+0x4a/0xc0 fs/open.c:1557 [<000000004060032b>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<000000004060032b>] do_syscall_64+0x3c/0x90 arch/x86/entry/common.c:80 [<00000000e8d61c9b>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 ---8<--- In my syzkaller log, only this program had the MD5 operation. I ran this overnight but had no luck for now. ---8<--- 23:51:30 executing program 0: r0 = socket$inet(0x2, 0x4000000000000001, 0x0) setsockopt$inet_tcp_TCP_MD5SIG(r0, 0x6, 0xe, &(0x7f0000000780)={@in={{0x2, 0x0, @local}}, 0x0, 0x9, 0x6, 0x0, "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000030cf00"}, 0xd8) (async) bind$inet(r0, &(0x7f0000deb000)={0x2, 0x4e23, @multicast1}, 0x10) (async, rerun: 64) sendto$inet(r0, 0x0, 0x0, 0x200007b9, &(0x7f0000000040)={0x2, 0x4e23, @local}, 0x10) (async, rerun: 64) socket$inet6(0xa, 0x0, 0x0) (async) getsockopt$EBT_SO_GET_INIT_ENTRIES(0xffffffffffffffff, 0x0, 0x83, &(0x7f0000000080)={'filter\x00', 0x0, 0x4, 0x1000, [0x0, 0x8, 0x1, 0x1, 0x0, 0x7fffffff], 0x4, &(0x7f0000000000)=[{}, {}, {}, {}], &(0x7f0000000880)=""/4096}, 0x0) (async, rerun: 32) socket(0x0, 0x0, 0x0) (async, rerun: 32) r1 = openat2(0xffffffffffffffff, &(0x7f0000000100)='./file0\x00', &(0x7f0000000140)={0x20000, 0x8, 0x14}, 0x18) bind$inet(r1, &(0x7f0000000180)={0x2, 0x4e22, @remote}, 0x10) (async) sendmsg$nl_route(0xffffffffffffffff, 0x0, 0x0) ---8<--- > > You could not have KMEMLEAK in the kernel, and run the repro a thousand times. > > Then compare /proc/slabinfo before/after.
