diff options
| author | Ben Horgan <ben.horgan@arm.com> | 2025-12-19 18:11:03 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2026-01-08 19:03:15 +0000 |
| commit | c2803bd580db226008aabf2fb2f0c9a7d3b5d0de (patch) | |
| tree | 5a193d3486a6ba4051658c0c5009cd8430418cdf | |
| parent | dd4d71f587f3908f058b516d3793aaed66cfb692 (diff) | |
arm_mpam: Stop using uninitialized variables in __ris_msmon_read()
Dan has reported two uses of uninitialized variables in __ris_msmon_read().
If an unknown monitor type is encountered then the local variable, now, is
used uninitialized. Fix this by returning early on error. If a non-mbwu
monitor is being read then the local variable, overflow, is not initialized
but still read. Initialize it to false as overflow is not relevant for csu
monitors.
Fixes: 823e7c3712c5 ("arm_mpam: Add mpam_msmon_read() to read monitor value")
Fixes: 9e5afb7c3283 ("arm_mpam: Use long MBWU counters if supported")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202512091519.RBwiJcSq-lkp@intel.com/
Closes: https://lore.kernel.org/r/202512100547.N7QPYgfb-lkp@intel.com/
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | drivers/resctrl/mpam_devices.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 0b5b158e1aaf..b495d5291868 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -1072,7 +1072,7 @@ static void __ris_msmon_read(void *arg) u64 now; bool nrdy = false; bool config_mismatch; - bool overflow; + bool overflow = false; struct mon_read *m = arg; struct mon_cfg *ctx = m->ctx; bool reset_on_next_read = false; @@ -1176,10 +1176,11 @@ static void __ris_msmon_read(void *arg) } mpam_mon_sel_unlock(msc); - if (nrdy) { + if (nrdy) m->err = -EBUSY; + + if (m->err) return; - } *m->val += now; } |