-
由 Theodore Ts'o 提交于
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: 8f7d89f3 ("jbd2: transaction reservation support") Signed-off-by: NTheodore Ts'o <tytso@mit.edu> Reviewed-by: NAndreas Dilger <adilger@dilger.ca> Reviewed-by: NJan Kara <jack@suse.cz>
b2569260