[syzbot] memory leak in __register_sysctl_table

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7a68065eb9cd Merge tag 'gpio-fixes-for-v5.19-rc2' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1432d953f00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b8e07e4ed17ee546
dashboard link: https://syzkaller.appspot.com/bug?extid=9f160a43b2cf201cbe65
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=1297ba43f00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14bf34a7f00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9f160a43b2cf201cbe65@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff8881016dfa00 (size 256):
  comm "syz-executor201", pid 3662, jiffies 4294969093 (age 12.970s)
  hex dump (first 32 bytes):
    00 90 da 0d 81 88 ff ff 00 00 00 00 01 00 00 00  ................
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff816fe96b>] kmalloc include/linux/slab.h:605 [inline]
    [<ffffffff816fe96b>] kzalloc include/linux/slab.h:733 [inline]
    [<ffffffff816fe96b>] __register_sysctl_table+0x7b/0x7f0 fs/proc/proc_sysctl.c:1344
    [<ffffffff82219a5a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112
    [<ffffffff822196d2>] create_ipc_ns ipc/namespace.c:63 [inline]
    [<ffffffff822196d2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91
    [<ffffffff8127de6c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90
    [<ffffffff8127e88b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
    [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165
    [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline]
    [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline]
    [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234
    [<ffffffff845abc55>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff845abc55>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

BUG: memory leak
unreferenced object 0xffff88810edf7b00 (size 256):
  comm "syz-executor201", pid 3662, jiffies 4294969093 (age 12.970s)
  hex dump (first 32 bytes):
    78 7b df 0e 81 88 ff ff 00 00 00 00 01 00 00 00  x{..............
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff816fee99>] kmalloc include/linux/slab.h:605 [inline]
    [<ffffffff816fee99>] kzalloc include/linux/slab.h:733 [inline]
    [<ffffffff816fee99>] new_dir fs/proc/proc_sysctl.c:978 [inline]
    [<ffffffff816fee99>] get_subdir fs/proc/proc_sysctl.c:1022 [inline]
    [<ffffffff816fee99>] __register_sysctl_table+0x5a9/0x7f0 fs/proc/proc_sysctl.c:1373
    [<ffffffff82219a5a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112
    [<ffffffff822196d2>] create_ipc_ns ipc/namespace.c:63 [inline]
    [<ffffffff822196d2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91
    [<ffffffff8127de6c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90
    [<ffffffff8127e88b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
    [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165
    [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline]
    [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline]
    [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234
    [<ffffffff845abc55>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff845abc55>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

BUG: memory leak
unreferenced object 0xffff888101926f00 (size 256):
  comm "syz-executor201", pid 3662, jiffies 4294969093 (age 12.970s)
  hex dump (first 32 bytes):
    78 6f 92 01 81 88 ff ff 00 00 00 00 01 00 00 00  xo..............
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff816fee99>] kmalloc include/linux/slab.h:605 [inline]
    [<ffffffff816fee99>] kzalloc include/linux/slab.h:733 [inline]
    [<ffffffff816fee99>] new_dir fs/proc/proc_sysctl.c:978 [inline]
    [<ffffffff816fee99>] get_subdir fs/proc/proc_sysctl.c:1022 [inline]
    [<ffffffff816fee99>] __register_sysctl_table+0x5a9/0x7f0 fs/proc/proc_sysctl.c:1373
    [<ffffffff82219a5a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112
    [<ffffffff822196d2>] create_ipc_ns ipc/namespace.c:63 [inline]
    [<ffffffff822196d2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91
    [<ffffffff8127de6c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90
    [<ffffffff8127e88b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
    [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165
    [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline]
    [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline]
    [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234
    [<ffffffff845abc55>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff845abc55>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory


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