diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-11-09 17:48:59 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-11-13 20:51:37 -0800 |
| commit | 73bde5a3294853947252cd9092a3517c7cb0cd2d (patch) | |
| tree | b10fc69b8c99caf44ac193dc0cf9bb8e92e3633d /drivers/ptp/ptp_chardev.c | |
| parent | 4b3812d90b2c93723adf4b6ce99240d301f7d5f9 (diff) | |
ptp: annotate data-race around q->head and q->tail
As I was working on a syzbot report, I found that KCSAN would
probably complain that reading q->head or q->tail without
barriers could lead to invalid results.
Add corresponding READ_ONCE() and WRITE_ONCE() to avoid
load-store tearing.
Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Link: https://lore.kernel.org/r/20231109174859.3995880-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/ptp/ptp_chardev.c')
| -rw-r--r-- | drivers/ptp/ptp_chardev.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c index 3f7a74788802..7513018c9f9a 100644 --- a/drivers/ptp/ptp_chardev.c +++ b/drivers/ptp/ptp_chardev.c @@ -572,7 +572,8 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, for (i = 0; i < cnt; i++) { event[i] = queue->buf[queue->head]; - queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS; + /* Paired with READ_ONCE() in queue_cnt() */ + WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS); } spin_unlock_irqrestore(&queue->lock, flags); |