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) You could not have KMEMLEAK in the kernel, and run the repro a thousand times. Then compare /proc/slabinfo before/after.
