zram: don't free statically defined names

BugLink: https://bugs.launchpad.net/bugs/2097393

[ Upstream commit 486fd58af7ac1098b68370b1d4d9f94a2a1c7124 ]

When CONFIG_ZRAM_MULTI_COMP isn't set ZRAM_SECONDARY_COMP can hold
default_compressor, because it's the same offset as ZRAM_PRIMARY_COMP, so
we need to make sure that we don't attempt to kfree() the statically
defined compressor name.

This is detected by KASAN.

==================================================================
  Call trace:
   kfree+0x60/0x3a0
   zram_destroy_comps+0x98/0x198 [zram]
   zram_reset_device+0x22c/0x4a8 [zram]
   reset_store+0x1bc/0x2d8 [zram]
   dev_attr_store+0x44/0x80
   sysfs_kf_write+0xfc/0x188
   kernfs_fop_write_iter+0x28c/0x428
   vfs_write+0x4dc/0x9b8
   ksys_write+0x100/0x1f8
   __arm64_sys_write+0x74/0xb8
   invoke_syscall+0xd8/0x260
   el0_svc_common.constprop.0+0xb4/0x240
   do_el0_svc+0x48/0x68
   el0_svc+0x40/0xc8
   el0t_64_sync_handler+0x120/0x130
   el0t_64_sync+0x190/0x198
==================================================================

Link: https://lkml.kernel.org/r/20240923164843.1117010-1-andrej.skvortzov@gmail.com
Fixes: 684826f8271a ("zram: free secondary algorithms names")
Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reported-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Closes: https://lore.kernel.org/lkml/57130e48-dbb6-4047-a8c7-ebf5aaea93f4@linux.vnet.ibm.com/
Tested-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Cc: Chris Li <chrisl@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
This commit is contained in:
Andrey Skvortsov
2024-10-09 13:51:40 +09:00
committed by Mehmet Basaran
parent 92b3c01f98
commit b44c8c4064
+4 -2
View File
@@ -1980,8 +1980,10 @@ static void zram_destroy_comps(struct zram *zram)
zram->num_active_comps--;
}
for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
kfree(zram->comp_algs[prio]);
for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
/* Do not free statically defined compression algorithms */
if (zram->comp_algs[prio] != default_compressor)
kfree(zram->comp_algs[prio]);
zram->comp_algs[prio] = NULL;
}
}