* [PATCH net-next V8 2/2] ptp: fix corrupted list in ptp_open
[not found] <20231106143127.3936908-3-eadavis@qq.com>
@ 2023-11-06 14:31 ` Edward Adam Davis
2023-11-07 6:13 ` Richard Cochran
0 siblings, 1 reply; 2+ messages in thread
From: Edward Adam Davis @ 2023-11-06 14:31 UTC (permalink / raw)
To: richardcochran
Cc: davem, eadavis, habetsm.xilinx, jeremy, linux-kernel, netdev,
reibax, syzbot+df3f3ef31f60781fa911
There is no lock protection when writing ptp->tsevqs in ptp_open() and
ptp_release(), which can cause data corruption, use spin lock to avoid this
issue.
Moreover, ptp_release() should not be used to release the queue in ptp_read(),
and it should be deleted altogether.
Reported-and-tested-by: syzbot+df3f3ef31f60781fa911@syzkaller.appspotmail.com
Fixes: 8f5de6fb2453 ("ptp: support multiple timestamp event readers")
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
drivers/ptp/ptp_chardev.c | 21 ++++++++++++---------
drivers/ptp/ptp_clock.c | 8 ++++++--
drivers/ptp/ptp_private.h | 1 +
3 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 282cd7d24077..473b6d992507 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -108,6 +108,7 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
container_of(pccontext->clk, struct ptp_clock, clock);
struct timestamp_event_queue *queue;
char debugfsname[32];
+ unsigned long flags;
queue = kzalloc(sizeof(*queue), GFP_KERNEL);
if (!queue)
@@ -119,7 +120,9 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
}
bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
spin_lock_init(&queue->lock);
+ spin_lock_irqsave(&ptp->tsevqs_lock, flags);
list_add_tail(&queue->qlist, &ptp->tsevqs);
+ spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
pccontext->private_clkdata = queue;
/* Debugfs contents */
@@ -139,16 +142,16 @@ int ptp_release(struct posix_clock_context *pccontext)
{
struct timestamp_event_queue *queue = pccontext->private_clkdata;
unsigned long flags;
+ struct ptp_clock *ptp =
+ container_of(pccontext->clk, struct ptp_clock, clock);
- if (queue) {
- debugfs_remove(queue->debugfs_instance);
- pccontext->private_clkdata = NULL;
- spin_lock_irqsave(&queue->lock, flags);
- list_del(&queue->qlist);
- spin_unlock_irqrestore(&queue->lock, flags);
- bitmap_free(queue->mask);
- kfree(queue);
- }
+ debugfs_remove(queue->debugfs_instance);
+ pccontext->private_clkdata = NULL;
+ spin_lock_irqsave(&ptp->tsevqs_lock, flags);
+ list_del(&queue->qlist);
+ spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
+ bitmap_free(queue->mask);
+ kfree(queue);
return 0;
}
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 3d1b0a97301c..b901f2910963 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -179,11 +179,11 @@ static void ptp_clock_release(struct device *dev)
mutex_destroy(&ptp->pincfg_mux);
mutex_destroy(&ptp->n_vclocks_mux);
/* Delete first entry */
+ spin_lock_irqsave(&ptp->tsevqs_lock, flags);
tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
qlist);
- spin_lock_irqsave(&tsevq->lock, flags);
list_del(&tsevq->qlist);
- spin_unlock_irqrestore(&tsevq->lock, flags);
+ spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
bitmap_free(tsevq->mask);
kfree(tsevq);
debugfs_remove(ptp->debugfs_root);
@@ -247,6 +247,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
if (!queue)
goto no_memory_queue;
list_add_tail(&queue->qlist, &ptp->tsevqs);
+ spin_lock_init(&ptp->tsevqs_lock);
queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
if (!queue->mask)
goto no_memory_bitmap;
@@ -407,6 +408,7 @@ void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
{
struct timestamp_event_queue *tsevq;
struct pps_event_time evt;
+ unsigned long flags;
switch (event->type) {
@@ -415,10 +417,12 @@ void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
case PTP_CLOCK_EXTTS:
/* Enqueue timestamp on selected queues */
+ spin_lock_irqsave(&ptp->tsevqs_lock, flags);
list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
if (test_bit((unsigned int)event->index, tsevq->mask))
enqueue_external_timestamp(tsevq, event);
}
+ spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
wake_up_interruptible(&ptp->tsev_wq);
break;
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 52f87e394aa6..35fde0a05746 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 */
+ spinlock_t tsevqs_lock; /* protects tsevqs from concurrent access */
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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