5.4-stable review patch. If anyone has any objections, please let me know.
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From: Peter Oberparleiter oberpar@linux.ibm.com
[ Upstream commit bf365071ea92b9579d5a272679b74052a5643e35 ]
When a task waiting for completion of a Store Data operation is interrupted, an attempt is made to halt this operation. If this attempt fails due to a hardware or firmware problem, there is a chance that the SCLP facility might store data into buffers referenced by the original operation at a later time.
Handle this situation by not releasing the referenced data buffers if the halt attempt fails. For current use cases, this might result in a leak of few pages of memory in case of a rare hardware/firmware malfunction.
Reviewed-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Peter Oberparleiter oberpar@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/s390/char/sclp_sd.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/char/sclp_sd.c b/drivers/s390/char/sclp_sd.c index 1e244f78f1929..64581433c3349 100644 --- a/drivers/s390/char/sclp_sd.c +++ b/drivers/s390/char/sclp_sd.c @@ -319,8 +319,14 @@ static int sclp_sd_store_data(struct sclp_sd_data *result, u8 di) &esize); if (rc) { /* Cancel running request if interrupted */ - if (rc == -ERESTARTSYS) - sclp_sd_sync(page, SD_EQ_HALT, di, 0, 0, NULL, NULL); + if (rc == -ERESTARTSYS) { + if (sclp_sd_sync(page, SD_EQ_HALT, di, 0, 0, NULL, NULL)) { + pr_warn("Could not stop Store Data request - leaking at least %zu bytes\n", + (size_t)dsize * PAGE_SIZE); + data = NULL; + asce = 0; + } + } vfree(data); goto out; }