diff options
| author | Colin Foster <colin.foster@in-advantage.com> | 2022-02-10 07:04:51 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-02-10 11:44:41 -0800 |
| commit | 7fbf6795d127a3b1bb39b0e42579904cf6db1624 (patch) | |
| tree | d0cb98a9fa64a98280eeea6e5c9456ae29900f63 | |
| parent | c4416f5c2eb3ed48dfba265e628a6e52da962f03 (diff) | |
| download | linux-7fbf6795d127a3b1bb39b0e42579904cf6db1624.tar.bz2 | |
net: mscc: ocelot: fix mutex lock error during ethtool stats read
An ongoing workqueue populates the stats buffer. At the same time, a user
might query the statistics. While writing to the buffer is mutex-locked,
reading from the buffer wasn't. This could lead to buggy reads by ethtool.
This patch fixes the former blamed commit, but the bug was introduced in
the latter.
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Fixes: 1e1caa9735f90 ("ocelot: Clean up stats update deferred work")
Fixes: a556c76adc052 ("net: mscc: Add initial Ocelot switch support")
Reported-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/all/20220210150451.416845-2-colin.foster@in-advantage.com/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ethernet/mscc/ocelot.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c index 354e4474bcc3..e6de86552df0 100644 --- a/drivers/net/ethernet/mscc/ocelot.c +++ b/drivers/net/ethernet/mscc/ocelot.c @@ -1745,12 +1745,11 @@ void ocelot_get_strings(struct ocelot *ocelot, int port, u32 sset, u8 *data) } EXPORT_SYMBOL(ocelot_get_strings); +/* Caller must hold &ocelot->stats_lock */ static void ocelot_update_stats(struct ocelot *ocelot) { int i, j; - mutex_lock(&ocelot->stats_lock); - for (i = 0; i < ocelot->num_phys_ports; i++) { /* Configure the port to read the stats from */ ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(i), SYS_STAT_CFG); @@ -1769,8 +1768,6 @@ static void ocelot_update_stats(struct ocelot *ocelot) ~(u64)U32_MAX) + val; } } - - mutex_unlock(&ocelot->stats_lock); } static void ocelot_check_stats_work(struct work_struct *work) @@ -1779,7 +1776,9 @@ static void ocelot_check_stats_work(struct work_struct *work) struct ocelot *ocelot = container_of(del_work, struct ocelot, stats_work); + mutex_lock(&ocelot->stats_lock); ocelot_update_stats(ocelot); + mutex_unlock(&ocelot->stats_lock); queue_delayed_work(ocelot->stats_queue, &ocelot->stats_work, OCELOT_STATS_CHECK_DELAY); @@ -1789,12 +1788,16 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data) { int i; + mutex_lock(&ocelot->stats_lock); + /* check and update now */ ocelot_update_stats(ocelot); /* Copy all counters */ for (i = 0; i < ocelot->num_stats; i++) *data++ = ocelot->stats[port * ocelot->num_stats + i]; + + mutex_unlock(&ocelot->stats_lock); } EXPORT_SYMBOL(ocelot_get_ethtool_stats); |