diff options
| author | Tom Hughes <tomhughes@chromium.org> | 2020-10-08 10:28:17 -0700 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2020-10-09 23:34:52 +0000 |
| commit | 19260e58511d3a2e6953be36930b410f129a33dc (patch) | |
| tree | c9f62f143d3f0e2258524895bda3d62cd32b8b36 | |
| parent | 4afe356a38c7599e83ac637caa385728ce397a0b (diff) | |
| download | chrome-ec-19260e58511d3a2e6953be36930b410f129a33dc.tar.gz | |
chip/stm32: Only use a mutex when not in interrupt context
Mutexes shouldn't be used in interrupt context. An ASSERT was added in
mutex_lock to verify this commit
e6956209119d2b2c1f45401855019e3a0a2f7dd5.
There are cases where bkpdata_write can be called from an interrupt
context, such as this stack trace that occurs when adding entropy from
RO on dartmonkey/icetower (stack captured with Segger J-Trace):
> rollbackaddent 1234
panic_assert_fail panic_output.c:132
mutex_lock task.c:889
bkpdata_write bkpdata.c:35
bkpdata_write bkpdata.c:24
bkpdata_write_reset_flags bkpdata.c:86
chip_save_reset_flags system.c:366
system_reset system.c:366
panic_reboot panic_output.c:114
report_panic panic.c:339
exception_panic panic.c:350
Validation of the fix was checked with the "rollback_region1" unit test,
which failed before the change and works after.
BRANCH=none
BUG=b:170147314
TEST=./test/run_device_tests.py -b dartmonkey -t rollback_region1
Signed-off-by: Tom Hughes <tomhughes@chromium.org>
Change-Id: Ie5509ec024e94b48c786199ccbb81ce93fafe547
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2462545
Reviewed-by: Edward Hill <ecgh@chromium.org>
| -rw-r--r-- | chip/stm32/bkpdata.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/chip/stm32/bkpdata.c b/chip/stm32/bkpdata.c index 2b26ace7ea..bb1a7a5de3 100644 --- a/chip/stm32/bkpdata.c +++ b/chip/stm32/bkpdata.c @@ -24,6 +24,7 @@ uint16_t bkpdata_read(enum bkpdata_index index) int bkpdata_write(enum bkpdata_index index, uint16_t value) { static struct mutex bkpdata_write_mutex; + int use_mutex = !in_interrupt_context(); if (index < 0 || index >= STM32_BKP_ENTRIES) return EC_ERROR_INVAL; @@ -32,7 +33,8 @@ int bkpdata_write(enum bkpdata_index index, uint16_t value) * Two entries share a single 32-bit register, lock mutex to prevent * read/mask/write races. */ - mutex_lock(&bkpdata_write_mutex); + if (use_mutex) + mutex_lock(&bkpdata_write_mutex); if (index & 1) { uint32_t val = STM32_BKP_DATA(index >> 1); val = (val & 0x0000FFFF) | (value << 16); @@ -42,7 +44,8 @@ int bkpdata_write(enum bkpdata_index index, uint16_t value) val = (val & 0xFFFF0000) | value; STM32_BKP_DATA(index >> 1) = val; } - mutex_unlock(&bkpdata_write_mutex); + if (use_mutex) + mutex_unlock(&bkpdata_write_mutex); return EC_SUCCESS; } |