This is a note to let you know that I've just added the patch titled
net-sysfs: Fix reference count leak
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-sysfs-fix-reference-count-leak.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon 27 Jan 2020 04:06:27 PM CET
From: Jouni Hogander <jouni.hogander@xxxxxxxxxx>
Date: Mon, 20 Jan 2020 09:51:03 +0200
Subject: net-sysfs: Fix reference count leak
From: Jouni Hogander <jouni.hogander@xxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/dev.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7322,8 +7322,10 @@ 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);
Patches currently in stable-queue which might be from jouni.hogander@xxxxxxxxxx are
queue-4.9/net-sysfs-fix-reference-count-leak.patch
