diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2018-04-18 11:49:31 -0400 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2018-12-02 00:00:18 +0100 |
| commit | fcb33641c55043c2f15304e86b195c017f4e57be (patch) | |
| tree | 53d5f36ecc8a5fa9cc5900097f24809c8c9da7eb /fs | |
| parent | 742d4cd3625f832fec482e8fbe245a4d07eade78 (diff) | |
ext4: set h_journal if there is a failure starting a reserved handle
commit b2569260d55228b617bd82aba6d0db2faeeb4116 upstream.
If ext4 tries to start a reserved handle via
jbd2_journal_start_reserved(), and the journal has been aborted, this
can result in a NULL pointer dereference. This is because the fields
h_journal and h_transaction in the handle structure share the same
memory, via a union, so jbd2_journal_start_reserved() will clear
h_journal before calling start_this_handle(). If this function fails
due to an aborted handle, h_journal will still be NULL, and the call
to jbd2_journal_free_reserved() will pass a NULL journal to
sub_reserve_credits().
This can be reproduced by running "kvm-xfstests -c dioread_nolock
generic/475".
Cc: stable@kernel.org # 3.11
Fixes: 8f7d89f36829b ("jbd2: transaction reservation support")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/jbd2/transaction.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 0c5e86530..9bf7d9885 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -515,6 +515,7 @@ int jbd2_journal_start_reserved(handle_t *handle, unsigned int type, */ ret = start_this_handle(journal, handle, GFP_NOFS); if (ret < 0) { + handle->h_journal = journal; jbd2_journal_free_reserved(handle); return ret; } |