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Message-ID: <tencent_2C67C6D2537B236F497823BCC457976F9705@qq.com>
Date: Tue, 31 Oct 2023 18:25:42 +0800
From: Edward Adam Davis <eadavis@...com>
To: habetsm.xilinx@...il.com
Cc: davem@...emloft.net,
linux-kernel@...r.kernel.org,
netdev@...r.kernel.org,
reibax@...il.com,
richardcochran@...il.com,
syzbot+df3f3ef31f60781fa911@...kaller.appspotmail.com,
syzkaller-bugs@...glegroups.com
Subject: [PATCH net-next V2] ptp: fix corrupted list in ptp_open
There is no lock protection when writing ptp->tsevqs in ptp_open(),
ptp_release(), which can cause data corruption, use mutex lock to avoid this
issue.
Moreover, ptp_release() should not be used to release the queue in ptp_read(),
and it should be deleted together.
Reported-and-tested-by: syzbot+df3f3ef31f60781fa911@...kaller.appspotmail.com
Fixes: 8f5de6fb2453 ("ptp: support multiple timestamp event readers")
Signed-off-by: Edward Adam Davis <eadavis@...com>
---
drivers/ptp/ptp_chardev.c | 11 +++++++++--
drivers/ptp/ptp_clock.c | 3 +++
drivers/ptp/ptp_private.h | 1 +
3 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 282cd7d24077..e31551d2697d 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -109,6 +109,9 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
struct timestamp_event_queue *queue;
char debugfsname[32];
+ if (mutex_lock_interruptible(&ptp->tsevq_mux))
+ return -ERESTARTSYS;
+
queue = kzalloc(sizeof(*queue), GFP_KERNEL);
if (!queue)
return -EINVAL;
@@ -132,15 +135,20 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
debugfs_create_u32_array("mask", 0444, queue->debugfs_instance,
&queue->dfs_bitmap);
+ mutex_unlock(&ptp->tsevq_mux);
return 0;
}
int ptp_release(struct posix_clock_context *pccontext)
{
struct timestamp_event_queue *queue = pccontext->private_clkdata;
+ struct ptp_clock *ptp =
+ container_of(pccontext->clk, struct ptp_clock, clock);
unsigned long flags;
if (queue) {
+ if (mutex_lock_interruptible(&ptp->tsevq_mux))
+ return -ERESTARTSYS;
debugfs_remove(queue->debugfs_instance);
pccontext->private_clkdata = NULL;
spin_lock_irqsave(&queue->lock, flags);
@@ -148,6 +156,7 @@ int ptp_release(struct posix_clock_context *pccontext)
spin_unlock_irqrestore(&queue->lock, flags);
bitmap_free(queue->mask);
kfree(queue);
+ mutex_unlock(&ptp->tsevq_mux);
}
return 0;
}
@@ -585,7 +594,5 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags,
free_event:
kfree(event);
exit:
- if (result < 0)
- ptp_release(pccontext);
return result;
}
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 3d1b0a97301c..7930db6ec18d 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -176,6 +176,7 @@ static void ptp_clock_release(struct device *dev)
ptp_cleanup_pin_groups(ptp);
kfree(ptp->vclock_index);
+ mutex_destroy(&ptp->tsevq_mux);
mutex_destroy(&ptp->pincfg_mux);
mutex_destroy(&ptp->n_vclocks_mux);
/* Delete first entry */
@@ -247,6 +248,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
if (!queue)
goto no_memory_queue;
list_add_tail(&queue->qlist, &ptp->tsevqs);
+ mutex_init(&ptp->tsevq_mux);
queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
if (!queue->mask)
goto no_memory_bitmap;
@@ -356,6 +358,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
if (ptp->kworker)
kthread_destroy_worker(ptp->kworker);
kworker_err:
+ mutex_destroy(&ptp->tsevq_mux);
mutex_destroy(&ptp->pincfg_mux);
mutex_destroy(&ptp->n_vclocks_mux);
bitmap_free(queue->mask);
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 52f87e394aa6..1525bd2059ba 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -44,6 +44,7 @@ struct ptp_clock {
struct pps_device *pps_source;
long dialed_frequency; /* remembers the frequency adjustment */
struct list_head tsevqs; /* timestamp fifo list */
+ struct mutex tsevq_mux; /* one process at a time reading the fifo */
struct mutex pincfg_mux; /* protect concurrent info->pin_config access */
wait_queue_head_t tsev_wq;
int defunct; /* tells readers to go away when clock is being removed */
--
2.25.1
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