Re: [PATCH v3 2/5] fs: Check if utf8 encoding is loaded before calling utf8_unload()
From: Gabriel Krisman Bertazi <hidden>
Date: 2021-03-23 19:11:37
Also in:
linux-f2fs-devel, linux-fsdevel, lkml
Shreeya Patel [off-list ref] writes:
utf8_unload is being called if CONFIG_UNICODE is enabled. The ifdef block doesn't check if utf8 encoding has been loaded or not before calling the utf8_unload() function. This is not the expected behavior since it would sometimes lead to unloading utf8 even before loading it. Hence, add a condition which will check if sb->encoding is NOT NULL before calling the utf8_unload().
Just to mention this used to be safe, since it was just doing a kfree(NULL), but won't be anymore after the rest of this series. Reviewed-by: Gabriel Krisman Bertazi <redacted>
quoted hunk
Signed-off-by: Shreeya Patel <redacted> --- Changes in v3 - Add this patch to the series which checks if utf8 encoding was loaded before calling uft8_unload(). fs/ext4/super.c | 6 ++++-- fs/f2fs/super.c | 9 ++++++--- 2 files changed, 10 insertions(+), 5 deletions(-)diff --git a/fs/ext4/super.c b/fs/ext4/super.c index ad34a3727..e438d14f9 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c@@ -1259,7 +1259,8 @@ static void ext4_put_super(struct super_block *sb) fs_put_dax(sbi->s_daxdev); fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy); #ifdef CONFIG_UNICODE - utf8_unload(sb->s_encoding); + if (sb->s_encoding) + utf8_unload(sb->s_encoding); #endif kfree(sbi); }@@ -5165,7 +5166,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) crypto_free_shash(sbi->s_chksum_driver); #ifdef CONFIG_UNICODE - utf8_unload(sb->s_encoding); + if (sb->s_encoding) + utf8_unload(sb->s_encoding); #endif #ifdef CONFIG_QUOTAdiff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 706979375..0a04983c2 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c@@ -1430,7 +1430,8 @@ static void f2fs_put_super(struct super_block *sb) for (i = 0; i < NR_PAGE_TYPE; i++) kvfree(sbi->write_io[i]); #ifdef CONFIG_UNICODE - utf8_unload(sb->s_encoding); + if (sb->s_encoding) + utf8_unload(sb->s_encoding); #endif kfree(sbi); }@@ -4073,8 +4074,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) kvfree(sbi->write_io[i]); #ifdef CONFIG_UNICODE - utf8_unload(sb->s_encoding); - sb->s_encoding = NULL; + if (sb->s_encoding) { + utf8_unload(sb->s_encoding); + sb->s_encoding = NULL; + } #endif free_options: #ifdef CONFIG_QUOTA
-- Gabriel Krisman Bertazi