zram: free secondary algorithms names

sergey-senozhatsky · mehmetb0 · commit f58ee48a3d71 · 2025-02-14T15:50:17.000+03:00
BugLink: https://bugs.launchpad.net/bugs/2097301 [ Upstream commit 684826f ] We need to kfree() secondary algorithms names when reset zram device that had multi-streams, otherwise we leak memory. [senozhatsky@chromium.org: kfree(NULL) is legal] Link: https://lkml.kernel.org/r/20240917013021.868769-1-senozhatsky@chromium.org Link: https://lkml.kernel.org/r/20240911025600.3681789-1-senozhatsky@chromium.org Fixes: 001d927 ("zram: add recompression algorithm sysfs knob") Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> CVE-2024-50064 Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com> Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
@@ -1979,6 +1979,11 @@ static void zram_destroy_comps(struct zram *zram)
 		zcomp_destroy(comp);
 		zram->num_active_comps--;
 	}
+
+	for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
+		kfree(zram->comp_algs[prio]);
+		zram->comp_algs[prio] = NULL;
+	}
 }
 
 static void zram_reset_device(struct zram *zram)

Original file line number	Diff line number	Diff line change
`@@ -1979,6 +1979,11 @@ static void zram_destroy_comps(struct zram *zram)`
`1979`	`1979`	`zcomp_destroy(comp);`
`1980`	`1980`	`zram->num_active_comps--;`
`1981`	`1981`	`}`
	`1982`	`+`
	`1983`	`+ for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {`
	`1984`	`+ kfree(zram->comp_algs[prio]);`
	`1985`	`+ zram->comp_algs[prio] = NULL;`
	`1986`	`+ }`
`1982`	`1987`	`}`
`1983`	`1988`
`1984`	`1989`	`static void zram_reset_device(struct zram *zram)`