From: Jouni Hogander jouni.hogander@unikie.com
[ Upstream commit cb626bf566eb4433318d35681286c494f04fedcc ]
Netdev_register_kobject is calling device_initialize. In case of error reference taken by device_initialize is not given up.
Drivers are supposed to call free_netdev in case of error. In non-error case the last reference is given up there and device release sequence is triggered. In error case this reference is kept and the release sequence is never started.
Fix this by setting reg_state as NETREG_UNREGISTERED if registering fails.
This is the rootcause for couple of memory leaks reported by Syzkaller:
BUG: memory leak unreferenced object 0xffff8880675ca008 (size 256): comm "netdev_register", pid 281, jiffies 4294696663 (age 6.808s) 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: [<0000000058ca4711>] kmem_cache_alloc_trace+0x167/0x280 [<000000002340019b>] device_add+0x882/0x1750 [<000000001d588c3a>] netdev_register_kobject+0x128/0x380 [<0000000011ef5535>] register_netdevice+0xa1b/0xf00 [<000000007fcf1c99>] __tun_chr_ioctl+0x20d5/0x3dd0 [<000000006a5b7b2b>] tun_chr_ioctl+0x2f/0x40 [<00000000f30f834a>] do_vfs_ioctl+0x1c7/0x1510 [<00000000fba062ea>] ksys_ioctl+0x99/0xb0 [<00000000b1c1b8d2>] __x64_sys_ioctl+0x78/0xb0 [<00000000984cabb9>] do_syscall_64+0x16f/0x580 [<000000000bde033d>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [<00000000e6ca2d9f>] 0xffffffffffffffff
BUG: memory leak unreferenced object 0xffff8880668ba588 (size 8): comm "kobject_set_nam", pid 286, jiffies 4294725297 (age 9.871s) hex dump (first 8 bytes): 6e 72 30 00 cc be df 2b nr0....+ backtrace: [<00000000a322332a>] __kmalloc_track_caller+0x16e/0x290 [<00000000236fd26b>] kstrdup+0x3e/0x70 [<00000000dd4a2815>] kstrdup_const+0x3e/0x50 [<0000000049a377fc>] kvasprintf_const+0x10e/0x160 [<00000000627fc711>] kobject_set_name_vargs+0x5b/0x140 [<0000000019eeab06>] dev_set_name+0xc0/0xf0 [<0000000069cb12bc>] netdev_register_kobject+0xc8/0x320 [<00000000f2e83732>] register_netdevice+0xa1b/0xf00 [<000000009e1f57cc>] __tun_chr_ioctl+0x20d5/0x3dd0 [<000000009c560784>] tun_chr_ioctl+0x2f/0x40 [<000000000d759e02>] do_vfs_ioctl+0x1c7/0x1510 [<00000000351d7c31>] ksys_ioctl+0x99/0xb0 [<000000008390040a>] __x64_sys_ioctl+0x78/0xb0 [<0000000052d196b7>] do_syscall_64+0x16f/0x580 [<0000000019af9236>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [<00000000bc384531>] 0xffffffffffffffff
v3 -> v4: Set reg_state to NETREG_UNREGISTERED if registering fails
v2 -> v3: * Replaced BUG_ON with WARN_ON in free_netdev and netdev_release
v1 -> v2: * Relying on driver calling free_netdev rather than calling put_device directly in error path
Reported-by: syzbot+ad8ca40ecd77896d51e2@syzkaller.appspotmail.com Cc: David Miller davem@davemloft.net Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Lukas Bulwahn lukas.bulwahn@gmail.com Signed-off-by: Jouni Hogander jouni.hogander@unikie.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/dev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -7667,8 +7667,10 @@ int register_netdevice(struct net_device goto err_uninit;
ret = netdev_register_kobject(dev); - if (ret) + if (ret) { + dev->reg_state = NETREG_UNREGISTERED; goto err_uninit; + } dev->reg_state = NETREG_REGISTERED;
__netdev_update_features(dev);