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[PATCH v2] udf: avoid uninitialized variable use

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A new warning about a real bug has come up from a recent cleanup:

fs/udf/inode.c: In function 'udf_setup_indirect_aext':
fs/udf/inode.c:1927:28: warning: 'adsize' may be used uninitialized in this function [-Wmaybe-uninitialized]

If the alloc_type is neither ICBTAG_FLAG_AD_SHORT nor ICBTAG_FLAG_AD_LONG,
the value of adsize is undefined. This changes the code to use zero for adsize
in that case, which may be the correct solution, though I have not looked
at the code in enough detail to know if it should be something else instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: fcea62babc81 ("udf: Factor out code for creating indirect extent")
---
sorry for missing another instance the first time around. The warning is
a bit unreliable and it seems in my first configuration I got it only
for one of the two instances that show it in other configuration.

After checking the remaining functions in this file for the same possible
problem, I found that the other functions use either 'BUG()' or 'return -EIO'
in the 'else' path, so I assume the two functions here should one of those
as well, but I don't know which.

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 5b83351041a4..42f68dd7e6ef 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1890,6 +1890,8 @@ int udf_setup_indirect_aext(struct inode *inode, int block,
 		adsize = sizeof(struct short_ad);
 	else if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(struct long_ad);
+	else
+		adsize = 0;
 
 	neloc.logicalBlockNum = block;
 	neloc.partitionReferenceNum = epos->block.partitionReferenceNum;
@@ -1963,6 +1965,8 @@ int __udf_add_aext(struct inode *inode, struct extent_position *epos,
 		adsize = sizeof(struct short_ad);
 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(struct long_ad);
+	else
+		adsize = 0;
 
 	if (!epos->bh) {
 		WARN_ON(iinfo->i_lenAlloc !=

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[PATCH] udf: avoid uninitialized variable use Arnd Bergmann <arnd@arndb.de> - 2016-01-01 13:50 +0100
  [PATCH v2] udf: avoid uninitialized variable use Arnd Bergmann <arnd@arndb.de> - 2016-01-01 15:30 +0100
    Re: [PATCH v2] udf: avoid uninitialized variable use Jan Kara <jack@suse.cz> - 2016-01-04 11:00 +0100
      Re: [PATCH v2] udf: avoid uninitialized variable use Arnd Bergmann <arnd@arndb.de> - 2016-01-04 11:50 +0100

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