On 14/07/2023 09:43, Ruidong Tian wrote:
Perf cs_etm session will failed when AUX buffer > 1G.
perf record -C 0 -m ,2G -e cs_etm// -- taskset -c 0 ls failed to mmap with 12 (Cannot allocate memory)
In coresight tmc driver, "nr_pages << PAGE_SHIFT" will overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). Explicit convert nr_pages to 64 bit to avoid overflow.
Hi Ruidong,
I couldn't reproduce this exact issue with the error message in the commit message. Is it not another manifestation related to this change [1]? I don't actually get any error message, but I was able to get a warning in dmesg even with [1] applied.
Does the overflow not result in a successful session but with the wrong buffer size?
I think the change makes sense, but maybe we also need a check for MAX_ORDER because I can trigger the same WARN_ON from [1]. Or maybe I'm a bit confused because of the other change and not being able to reproduce this exactly coming at the same time.
[1]: https://lore.kernel.org/bpf/20230711014120.53461-1-xueshuai@linux.alibaba.co...
Thanks James
Signed-off-by: Ruidong Tian tianruidong@linux.alibaba.com
drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +- drivers/hwtracing/coresight/coresight-tmc.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 766325de0e29..1425ecd1cf78 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event, * than the size requested via sysfs. */ if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT), 0, node, NULL);diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index b97da39652d2..0ee48c5ba764 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table, static inline unsigned long tmc_sg_table_buf_size(struct tmc_sg_table *sg_table) {
- return sg_table->data_pages.nr_pages << PAGE_SHIFT;
- return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
} struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);