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s390/sclp: Prevent release of buffer in I/O 

[ 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>
This commit is contained in:
Peter Oberparleiter 2024-06-20 14:20:27 +02:00 committed by Greg Kroah-Hartman
parent 6dacca9fbe
commit 1e8b7fb427
1 changed files with 8 additions and 2 deletions
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10
drivers/s390/char/sclp_sd.c
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@ -320,8 +320,14 @@ 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;
}