[PATCH v5.10] ptp: Fix possible memory leak in ptp_clock_register()

[PATCH v5.10] ptp: Fix possible memory leak in ptp_clock_register()

[Shivani Agarwal]

From: Yang Yingliang <yangyingliang@huawei.com>

[ Upstream commit 4225fea1cb28370086e17e82c0f69bec2779dca0 ]

I got memory leak as follows when doing fault injection test:

unreferenced object 0xffff88800906c618 (size 8):
  comm "i2c-idt82p33931", pid 4421, jiffies 4294948083 (age 13.188s)
  hex dump (first 8 bytes):
    70 74 70 30 00 00 00 00                          ptp0....
  backtrace:
    [<00000000312ed458>] __kmalloc_track_caller+0x19f/0x3a0
    [<0000000079f6e2ff>] kvasprintf+0xb5/0x150
    [<0000000026aae54f>] kvasprintf_const+0x60/0x190
    [<00000000f323a5f7>] kobject_set_name_vargs+0x56/0x150
    [<000000004e35abdd>] dev_set_name+0xc0/0x100
    [<00000000f20cfe25>] ptp_clock_register+0x9f4/0xd30 [ptp]
    [<000000008bb9f0de>] idt82p33_probe.cold+0x8b6/0x1561 [ptp_idt82p33]

When posix_clock_register() returns an error, the name allocated
in dev_set_name() will be leaked, the put_device() should be used
to give up the device reference, then the name will be freed in
kobject_cleanup() and other memory will be freed in ptp_clock_release().

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: a33121e5487b ("ptp: fix the race between the release of ptp_clock and cdev")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[Shivani: Modified to apply on 5.10.y, Removed 
kfree(ptp->vclock_index) in the ptach, since vclock_index is 
introduced in later versions]
Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com>
---
 drivers/ptp/ptp_clock.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index c895e26b1f17..869023f0987e 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -283,15 +283,20 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	/* Create a posix clock and link it to the device. */
 	err = posix_clock_register(&ptp->clock, &ptp->dev);
 	if (err) {
+		if (ptp->pps_source)
+			pps_unregister_source(ptp->pps_source);
+
+		if (ptp->kworker)
+			kthread_destroy_worker(ptp->kworker);
+
+		put_device(&ptp->dev);
+
 		pr_err("failed to create posix clock\n");
-		goto no_clock;
+		return ERR_PTR(err);
 	}
 
 	return ptp;
 
-no_clock:
-	if (ptp->pps_source)
-		pps_unregister_source(ptp->pps_source);
 no_pps:
 	ptp_cleanup_pin_groups(ptp);
 no_pin_groups:
-- 
2.40.4

Re: [PATCH v5.10] ptp: Fix possible memory leak in ptp_clock_register()

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
⚠️ Found follow-up fixes in mainline

The upstream commit SHA1 provided is correct: 4225fea1cb28370086e17e82c0f69bec2779dca0

WARNING: Author mismatch between patch and upstream commit:
Backport author: Shivani Agarwal <shivani.agarwal@broadcom.com>
Commit author: Yang Yingliang <yangyingliang@huawei.com>

Status in newer kernel trees:
6.15.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (exact SHA1)
6.1.y | Present (exact SHA1)
5.15.y | Present (exact SHA1)

Found fixes commits:
11195bf5a355 ptp: fix code indentation issues

Note: The patch differs from the upstream commit:
---
1:  4225fea1cb28 ! 1:  ed4903766eee ptp: Fix possible memory leak in ptp_clock_register()
    @@ Metadata
      ## Commit message ##
         ptp: Fix possible memory leak in ptp_clock_register()
     
    +    [ Upstream commit 4225fea1cb28370086e17e82c0f69bec2779dca0 ]
    +
         I got memory leak as follows when doing fault injection test:
     
         unreferenced object 0xffff88800906c618 (size 8):
    @@ Commit message
         Fixes: a33121e5487b ("ptp: fix the race between the release of ptp_clock and cdev")
         Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
         Signed-off-by: David S. Miller <davem@davemloft.net>
    +    Signed-off-by: Sasha Levin <sashal@kernel.org>
    +    [Shivani: Modified to apply on 5.10.y, Removed
    +    kfree(ptp->vclock_index) in the ptach, since vclock_index is
    +    introduced in later versions]
    +    Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com>
     
      ## drivers/ptp/ptp_clock.c ##
     @@ drivers/ptp/ptp_clock.c: struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
      	/* Create a posix clock and link it to the device. */
      	err = posix_clock_register(&ptp->clock, &ptp->dev);
      	if (err) {
    -+	        if (ptp->pps_source)
    -+	                pps_unregister_source(ptp->pps_source);
    -+
    -+		kfree(ptp->vclock_index);
    ++		if (ptp->pps_source)
    ++			pps_unregister_source(ptp->pps_source);
     +
     +		if (ptp->kworker)
    -+	                kthread_destroy_worker(ptp->kworker);
    ++			kthread_destroy_worker(ptp->kworker);
     +
     +		put_device(&ptp->dev);
     +

---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| origin/linux-5.10.y       | Success     | Success    |