exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree

commit daf60d6cca26e50d65dac374db92e58de745ad26 upstream.

The call stack shown below is a scenario in the Linux 4.19 kernel.
Allocating memory failed where exfat fs use kmalloc_array due to
system memory fragmentation, while the u-disk was inserted without
recognition.
Devices such as u-disk using the exfat file system are pluggable and
may be insert into the system at any time.
However, long-term running systems cannot guarantee the continuity of
physical memory. Therefore, it's necessary to address this issue.

Binder:2632_6: page allocation failure: order:4,
 mode:0x6040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
Call trace:
[242178.097582]  dump_backtrace+0x0/0x4
[242178.097589]  dump_stack+0xf4/0x134
[242178.097598]  warn_alloc+0xd8/0x144
[242178.097603]  __alloc_pages_nodemask+0x1364/0x1384
[242178.097608]  kmalloc_order+0x2c/0x510
[242178.097612]  kmalloc_order_trace+0x40/0x16c
[242178.097618]  __kmalloc+0x360/0x408
[242178.097624]  load_alloc_bitmap+0x160/0x284
[242178.097628]  exfat_fill_super+0xa3c/0xe7c
[242178.097635]  mount_bdev+0x2e8/0x3a0
[242178.097638]  exfat_fs_mount+0x40/0x50
[242178.097643]  mount_fs+0x138/0x2e8
[242178.097649]  vfs_kern_mount+0x90/0x270
[242178.097655]  do_mount+0x798/0x173c
[242178.097659]  ksys_mount+0x114/0x1ac
[242178.097665]  __arm64_sys_mount+0x24/0x34
[242178.097671]  el0_svc_common+0xb8/0x1b8
[242178.097676]  el0_svc_handler+0x74/0x90
[242178.097681]  el0_svc+0x8/0x340

By analyzing the exfat code,we found that continuous physical memory
is not required here,so kvmalloc_array is used can solve this problem.

Cc: stable@vger.kernel.org
Signed-off-by: gaoming <gaoming20@hihonor.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
index 9f42f25fab9203de6b3fd0902342f000febad6b4..e918decb37358636113b9379860b75cf2af8e736 100644 (file)
--- a/fs/exfat/balloc.c
+++ b/fs/exfat/balloc.c
@@ -69,7 +69,7 @@ static int exfat_allocate_bitmap(struct super_block *sb,
        }
        sbi->map_sectors = ((need_map_size - 1) >>
                        (sb->s_blocksize_bits)) + 1;
-       sbi->vol_amap = kmalloc_array(sbi->map_sectors,
+       sbi->vol_amap = kvmalloc_array(sbi->map_sectors,
                                sizeof(struct buffer_head *), GFP_KERNEL);
        if (!sbi->vol_amap)
                return -ENOMEM;
@@ -84,7 +84,7 @@ static int exfat_allocate_bitmap(struct super_block *sb,
                        while (j < i)
                                brelse(sbi->vol_amap[j++]);
 
-                       kfree(sbi->vol_amap);
+                       kvfree(sbi->vol_amap);
                        sbi->vol_amap = NULL;
                        return -EIO;
                }
@@ -138,7 +138,7 @@ void exfat_free_bitmap(struct exfat_sb_info *sbi)
        for (i = 0; i < sbi->map_sectors; i++)
                __brelse(sbi->vol_amap[i]);
 
-       kfree(sbi->vol_amap);
+       kvfree(sbi->vol_amap);
 }
 
 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)