[syzbot] [nfc?] memory leak in skb_copy (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f01e9fed845 Merge tag 'linux-watchdog-6.5-rc2' of git://w..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15fe3ef8a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=75da4f0a455bdbd3
dashboard link: https://syzkaller.appspot.com/bug?extid=6eb09d75211863f15e3e
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=162f1cbca80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/441fb7ea58b8/disk-3f01e9fe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8fa7790ba0c3/vmlinux-3f01e9fe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5e7a6471dadf/bzImage-3f01e9fe.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6eb09d...@syzkaller.appspotmail.com

BUG: memory leak
unreferenced object 0xffff88811fff5e00 (size 240):
comm "kworker/u4:0", pid 10, jiffies 4294989700 (age 28.220s)
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:
[<ffffffff83e1c0bd>] __alloc_skb+0x1fd/0x230 net/core/skbuff.c:634
[<ffffffff83e1efcf>] skb_copy+0x6f/0x180 net/core/skbuff.c:1925
[<ffffffff82c3526f>] virtual_nci_send+0x3f/0xb0 drivers/nfc/virtual_ncidev.c:58
[<ffffffff84990da9>] nci_send_frame+0x69/0xb0 net/nfc/nci/core.c:1347
[<ffffffff84990e82>] nci_cmd_work+0x92/0xc0 net/nfc/nci/core.c:1567
[<ffffffff812b19e4>] process_one_work+0x2c4/0x620 kernel/workqueue.c:2597
[<ffffffff812b233d>] worker_thread+0x5d/0x5c0 kernel/workqueue.c:2748
[<ffffffff812bbde3>] kthread+0x133/0x180 kernel/kthread.c:389
[<ffffffff81002b5f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

BUG: memory leak
unreferenced object 0xffff88810d74e500 (size 640):
comm "kworker/u4:0", pid 10, jiffies 4294989700 (age 28.220s)
hex dump (first 32 bytes):
20 00 01 01 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:
[<ffffffff83e18976>] kmalloc_reserve+0xe6/0x180 net/core/skbuff.c:559
[<ffffffff83e1bf95>] __alloc_skb+0xd5/0x230 net/core/skbuff.c:644
[<ffffffff83e1efcf>] skb_copy+0x6f/0x180 net/core/skbuff.c:1925
[<ffffffff82c3526f>] virtual_nci_send+0x3f/0xb0 drivers/nfc/virtual_ncidev.c:58
[<ffffffff84990da9>] nci_send_frame+0x69/0xb0 net/nfc/nci/core.c:1347
[<ffffffff84990e82>] nci_cmd_work+0x92/0xc0 net/nfc/nci/core.c:1567
[<ffffffff812b19e4>] process_one_work+0x2c4/0x620 kernel/workqueue.c:2597
[<ffffffff812b233d>] worker_thread+0x5d/0x5c0 kernel/workqueue.c:2748
[<ffffffff812bbde3>] kthread+0x133/0x180 kernel/kthread.c:389
[<ffffffff81002b5f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308



---
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[syzbot]

For archival purposes, forwarding an incoming command email to
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***

Subject: Private message regarding: [syzbot] [nfc?] memory leak in skb_copy (2)
Author: phin...@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
master
diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
index b027be0b0b6f..ac8226db54e2 100644
--- a/drivers/nfc/virtual_ncidev.c
+++ b/drivers/nfc/virtual_ncidev.c
@@ -20,26 +20,31 @@
NFC_PROTO_ISO14443_MASK | \
NFC_PROTO_ISO14443_B_MASK | \
NFC_PROTO_ISO15693_MASK)
+#define NCIDEV_RUNNING 0

struct virtual_nci_dev {
struct nci_dev *ndev;
struct mutex mtx;
struct sk_buff *send_buff;
struct wait_queue_head wq;
+ bool running;
};

static int virtual_nci_open(struct nci_dev *ndev)
{
+ struct virtual_nci_dev *vdev = nci_get_drvdata(ndev);
+
+ vdev->running = true;
return 0;
}

static int virtual_nci_close(struct nci_dev *ndev)
{
struct virtual_nci_dev *vdev = nci_get_drvdata(ndev);
-
mutex_lock(&vdev->mtx);
kfree_skb(vdev->send_buff);
vdev->send_buff = NULL;
+ vdev->running = false;
mutex_unlock(&vdev->mtx);

return 0;
@@ -50,7 +55,7 @@ static int virtual_nci_send(struct nci_dev *ndev, struct
sk_buff *skb)
struct virtual_nci_dev *vdev = nci_get_drvdata(ndev);

mutex_lock(&vdev->mtx);
- if (vdev->send_buff) {
+ if (vdev->send_buff || !vdev->running) {
mutex_unlock(&vdev->mtx);
kfree_skb(skb);
return -1;

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: [syzbot] [nfc?] memory leak in skb_copy (2)

[syzbot]

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file drivers/nfc/virtual_ncidev.c
patch: **** unexpected end of file in patch



Tested on:

commit: 5a82d69d Add linux-next specific files for 20231120
git tree: linux-next
kernel config: https://syzkaller.appspot.com/x/.config?x=ecfdf78a410c834

dashboard link: https://syzkaller.appspot.com/bug?extid=6eb09d75211863f15e3e
compiler:

patch: https://syzkaller.appspot.com/x/patch.diff?x=104ebaf4e80000

[syzbot]

patch: https://syzkaller.appspot.com/x/patch.diff?x=104f58bf680000

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+6eb09d...@syzkaller.appspotmail.com

Tested on:

commit: 5a82d69d Add linux-next specific files for 20231120
git tree: linux-next

console output: https://syzkaller.appspot.com/x/log.txt?x=10c62e24e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=49ad170540e06f6
dashboard link: https://syzkaller.appspot.com/bug?extid=6eb09d75211863f15e3e
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=16091d10e80000

Note: testing is done by a robot and is best-effort only.

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: [syzbot] [nfc?] memory leak in skb_copy (2)(test updated patch)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+6eb09d...@syzkaller.appspotmail.com

Tested on:

commit: 07b67795 Add linux-next specific files for 20231121
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13c090f0e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=824289224986e9d2

dashboard link: https://syzkaller.appspot.com/bug?extid=6eb09d75211863f15e3e
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=141f0348e80000