| Message ID | tencent_97D1BA12BBF933129EC01B1D4BB71BE92508@qq.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,V3] ptp: fix corrupted list in ptp_open | expand |
On Fri, Nov 03, 2023 at 09:15:03PM +0800, Edward Adam Davis wrote: > 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. The problem is the bogus call to ptp_release() in ptp_read(). Just delete that. No need for another mutex. Thanks, Richard
On Fri, Nov 03, 2023 at 04:18:44PM -0700, Richard Cochran wrote: > On Fri, Nov 03, 2023 at 09:15:03PM +0800, Edward Adam Davis wrote: > > 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. > > The problem is the bogus call to ptp_release() in ptp_read(). > > Just delete that. Like this... diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c index 282cd7d24077..27c1ef493617 100644 --- a/drivers/ptp/ptp_chardev.c +++ b/drivers/ptp/ptp_chardev.c @@ -585,7 +585,5 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, free_event: kfree(event); exit: - if (result < 0) - ptp_release(pccontext); return result; }
On Fri, Nov 03, 2023 at 09:15:03PM +0800, Edward Adam Davis wrote: > 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. Oh, now I see what you are fixing... > @@ -138,14 +143,19 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode) > 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; I don't think it is a good idea to return ERESTARTSYS on signal here. The release method needs to succeed. > debugfs_remove(queue->debugfs_instance); > pccontext->private_clkdata = NULL; > spin_lock_irqsave(&queue->lock, flags); This spin lock is wrong. The spin lock protects the queue, not the list of queues. The spin lock/unlock needs to be replaced with mutex lock/unlock. > list_del(&queue->qlist); > spin_unlock_irqrestore(&queue->lock, flags); > + mutex_unlock(&ptp->tsevq_mux); > bitmap_free(queue->mask); > kfree(queue); > } > 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 */ This comment is very misleading. The mutex does not protect the fifo. It protects 'tsevqs' from concurrent access. Thanks, Richard
On Fri, Nov 03, 2023 at 04:18:44PM -0700, Richard Cochran wrote:
> No need for another mutex.
Actually the mutex is needed.
Thanks,
Richard
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c index 282cd7d24077..6e9762a54b14 100644 --- a/drivers/ptp/ptp_chardev.c +++ b/drivers/ptp/ptp_chardev.c @@ -119,8 +119,13 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode) } bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS); spin_lock_init(&queue->lock); + if (mutex_lock_interruptible(&ptp->tsevq_mux)) { + kfree(queue); + return -ERESTARTSYS; + } list_add_tail(&queue->qlist, &ptp->tsevqs); pccontext->private_clkdata = queue; + mutex_unlock(&ptp->tsevq_mux); /* Debugfs contents */ sprintf(debugfsname, "0x%p", queue); @@ -138,14 +143,19 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode) 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); list_del(&queue->qlist); spin_unlock_irqrestore(&queue->lock, flags); + mutex_unlock(&ptp->tsevq_mux); bitmap_free(queue->mask); kfree(queue); } @@ -585,7 +595,5 @@ 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 */
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@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 | 12 ++++++++++-- drivers/ptp/ptp_clock.c | 3 +++ drivers/ptp/ptp_private.h | 1 + 3 files changed, 14 insertions(+), 2 deletions(-)