memory leak in nr_rx_frame

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    c5b44095 Merge tag 'trace-v5.2-rc1-2' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=135dcac4a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61dd9e15a761691d
dashboard link: https://syzkaller.appspot.com/bug?extid=d6636a36d3c34bd88938
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=159ca182a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ac4c5ca00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d6636a36d3c34bd88938@xxxxxxxxxxxxxxxxxxxxxxxxx

DRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready
executing program
executing program
BUG: memory leak
unreferenced object 0xffff88812393a800 (size 2048):
  comm "softirq", pid 0, jiffies 4294941705 (age 14.320s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    06 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............
  backtrace:
    [<0000000040c90168>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:55 [inline]
    [<0000000040c90168>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<0000000040c90168>] slab_alloc mm/slab.c:3326 [inline]
    [<0000000040c90168>] __do_kmalloc mm/slab.c:3658 [inline]
    [<0000000040c90168>] __kmalloc+0x161/0x2c0 mm/slab.c:3669
    [<00000000cf430504>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000cf430504>] sk_prot_alloc+0xd6/0x170 net/core/sock.c:1608
    [<00000000d895dd9d>] sk_alloc+0x35/0x2f0 net/core/sock.c:1662
    [<000000006dfffbd8>] nr_make_new net/netrom/af_netrom.c:479 [inline]
    [<000000006dfffbd8>] nr_rx_frame+0x3ba/0x8a0 net/netrom/af_netrom.c:962
    [<000000007e984676>] nr_loopback_timer+0x4e/0xd0  
net/netrom/nr_loopback.c:62
    [<0000000080a4b335>] call_timer_fn+0x45/0x1e0 kernel/time/timer.c:1322
    [<00000000b58aba8b>] expire_timers kernel/time/timer.c:1366 [inline]
    [<00000000b58aba8b>] __run_timers kernel/time/timer.c:1685 [inline]
    [<00000000b58aba8b>] __run_timers kernel/time/timer.c:1653 [inline]
    [<00000000b58aba8b>] run_timer_softirq+0x256/0x740  
kernel/time/timer.c:1698
    [<00000000c8260f2e>] __do_softirq+0x115/0x35e kernel/softirq.c:293
    [<00000000a50d1686>] invoke_softirq kernel/softirq.c:374 [inline]
    [<00000000a50d1686>] irq_exit+0xbb/0xe0 kernel/softirq.c:414
    [<00000000fb3290a8>] exiting_irq arch/x86/include/asm/apic.h:536  
[inline]
    [<00000000fb3290a8>] smp_apic_timer_interrupt+0x7b/0x170  
arch/x86/kernel/apic/apic.c:1068
    [<000000001caa821f>] apic_timer_interrupt+0xf/0x20  
arch/x86/entry/entry_64.S:806
    [<0000000092c5e05c>] native_safe_halt+0xe/0x10  
arch/x86/include/asm/irqflags.h:60
    [<000000006b3a6a48>] arch_cpu_idle+0xa/0x10  
arch/x86/kernel/process.c:571
    [<00000000a7e7084a>] default_idle_call+0x1e/0x40 kernel/sched/idle.c:94
    [<00000000f6ad9bb1>] cpuidle_idle_call kernel/sched/idle.c:154 [inline]
    [<00000000f6ad9bb1>] do_idle+0x1ea/0x2c0 kernel/sched/idle.c:263
    [<00000000711ac4f4>] cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354

BUG: memory leak
unreferenced object 0xffff88811f3ca1e0 (size 32):
  comm "softirq", pid 0, jiffies 4294941705 (age 14.320s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    03 00 00 00 03 00 00 00 0f 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000005fe8e8f4>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:55 [inline]
    [<000000005fe8e8f4>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<000000005fe8e8f4>] slab_alloc mm/slab.c:3326 [inline]
    [<000000005fe8e8f4>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<000000003ffaa535>] kmalloc include/linux/slab.h:547 [inline]
    [<000000003ffaa535>] kzalloc include/linux/slab.h:742 [inline]
    [<000000003ffaa535>] selinux_sk_alloc_security+0x48/0xb0  
security/selinux/hooks.c:5059
    [<000000001306812e>] security_sk_alloc+0x49/0x70  
security/security.c:2030
    [<00000000bbbf2d36>] sk_prot_alloc+0xf1/0x170 net/core/sock.c:1611
    [<00000000d895dd9d>] sk_alloc+0x35/0x2f0 net/core/sock.c:1662
    [<000000006dfffbd8>] nr_make_new net/netrom/af_netrom.c:479 [inline]
    [<000000006dfffbd8>] nr_rx_frame+0x3ba/0x8a0 net/netrom/af_netrom.c:962
    [<000000007e984676>] nr_loopback_timer+0x4e/0xd0  
net/netrom/nr_loopback.c:62
    [<0000000080a4b335>] call_timer_fn+0x45/0x1e0 kernel/time/timer.c:1322
    [<00000000b58aba8b>] expire_timers kernel/time/timer.c:1366 [inline]
    [<00000000b58aba8b>] __run_timers kernel/time/timer.c:1685 [inline]
    [<00000000b58aba8b>] __run_timers kernel/time/timer.c:1653 [inline]
    [<00000000b58aba8b>] run_timer_softirq+0x256/0x740  
kernel/time/timer.c:1698
    [<00000000c8260f2e>] __do_softirq+0x115/0x35e kernel/softirq.c:293
    [<00000000a50d1686>] invoke_softirq kernel/softirq.c:374 [inline]
    [<00000000a50d1686>] irq_exit+0xbb/0xe0 kernel/softirq.c:414
    [<00000000fb3290a8>] exiting_irq arch/x86/include/asm/apic.h:536  
[inline]
    [<00000000fb3290a8>] smp_apic_timer_interrupt+0x7b/0x170  
arch/x86/kernel/apic/apic.c:1068
    [<000000001caa821f>] apic_timer_interrupt+0xf/0x20  
arch/x86/entry/entry_64.S:806
    [<0000000092c5e05c>] native_safe_halt+0xe/0x10  
arch/x86/include/asm/irqflags.h:60
    [<000000006b3a6a48>] arch_cpu_idle+0xa/0x10  
arch/x86/kernel/process.c:571
    [<00000000a7e7084a>] default_idle_call+0x1e/0x40 kernel/sched/idle.c:94



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