| Message ID | tencent_D71CEB16EC1ECD0879366E9C2E216FBC950A@qq.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [PATCH-net-next] ptp: fix corrupted list in ptp_open | expand |
On Sun, Oct 29, 2023 at 10:09:42AM +0800, Edward Adam Davis wrote: > There is no lock protection when writing ptp->tsevqs in ptp_open(), ptp_read(), > ptp_release(), which can cause data corruption and increase mutual exclusion > to avoid this issue. -ENOPARSE How can lack of lock protection increase mutual exclusion? > Moreover, the queue should not be released in ptp_read() and should be deleted > together. The queue should be deleted togther? Huh? > @@ -543,6 +552,8 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, > cnt = EXTTS_BUFSIZE; > > cnt = cnt / sizeof(struct ptp_extts_event); > + if (mutex_lock_interruptible(&ptp->tsevq_mux)) > + return -ERESTARTSYS; This is not needed because the spin lock (timestamp_event_queue::lock) already protects the event queue. Thanks, Richard
On Sun, Oct 29, 2023 at 10:09:42AM +0800, Edward Adam Davis wrote: > @@ -585,7 +596,6 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, > free_event: > kfree(event); > exit: > - if (result < 0) > - ptp_release(pccontext); > + mutex_unlock(&ptp->tsevq_mux); > return result; > } This is the only hunk that makes sense. Keep this, but remove the rest, just like in your previous patches. Thanks, Richard
On Sun, 29 Oct 2023 12:49:00 -0700 Richard Cochran wrote: >> There is no lock protection when writing ptp->tsevqs in ptp_open(), ptp_read(), >> ptp_release(), which can cause data corruption and increase mutual exclusion >> to avoid this issue. > >-ENOPARSE > >How can lack of lock protection increase mutual exclusion? Use mutex lock to avoid this issue. > >> Moreover, the queue should not be released in ptp_read() and should be deleted >> together. > >The queue should be deleted togther? Huh? No. ptp_release() should not be used to release the queue in ptp_read(), and it should be deleted together. > >> @@ -543,6 +552,8 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, >> cnt = EXTTS_BUFSIZE; >> >> cnt = cnt / sizeof(struct ptp_extts_event); >> + if (mutex_lock_interruptible(&ptp->tsevq_mux)) >> + return -ERESTARTSYS; > >This is not needed because the spin lock (timestamp_event_queue::lock) >already protects the event queue. Yes, you are right, I will remove it. Thanks, edward
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c index 282cd7d24077..5546e4b4e083 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; } @@ -543,6 +552,8 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, cnt = EXTTS_BUFSIZE; cnt = cnt / sizeof(struct ptp_extts_event); + if (mutex_lock_interruptible(&ptp->tsevq_mux)) + return -ERESTARTSYS; if (wait_event_interruptible(ptp->tsev_wq, ptp->defunct || queue_cnt(queue))) { @@ -585,7 +596,6 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, free_event: kfree(event); exit: - if (result < 0) - ptp_release(pccontext); + mutex_unlock(&ptp->tsevq_mux); 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_read(), ptp_release(), which can cause data corruption and increase mutual exclusion to avoid this issue. Moreover, the queue should not be released in ptp_read() and 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 | 14 ++++++++++++-- drivers/ptp/ptp_clock.c | 3 +++ drivers/ptp/ptp_private.h | 1 + 3 files changed, 16 insertions(+), 2 deletions(-)