Patch "block: fix potential invalid pointer dereference in blk_add_partition" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    block: fix potential invalid pointer dereference in blk_add_partition

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     block-fix-potential-invalid-pointer-dereference-in-b.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bdc6aec76731e1723cee7ae41b2968d02e79374e
Author: Riyan Dhiman <riyandhiman14@xxxxxxxxx>
Date:   Wed Sep 11 18:59:54 2024 +0530

    block: fix potential invalid pointer dereference in blk_add_partition
    
    [ Upstream commit 26e197b7f9240a4ac301dd0ad520c0c697c2ea7d ]
    
    The blk_add_partition() function initially used a single if-condition
    (IS_ERR(part)) to check for errors when adding a partition. This was
    modified to handle the specific case of -ENXIO separately, allowing the
    function to proceed without logging the error in this case. However,
    this change unintentionally left a path where md_autodetect_dev()
    could be called without confirming that part is a valid pointer.
    
    This commit separates the error handling logic by splitting the
    initial if-condition, improving code readability and handling specific
    error scenarios explicitly. The function now distinguishes the general
    error case from -ENXIO without altering the existing behavior of
    md_autodetect_dev() calls.
    
    Fixes: b72053072c0b (block: allow partitions on host aware zone devices)
    Signed-off-by: Riyan Dhiman <riyandhiman14@xxxxxxxxx>
    Reviewed-by: Christoph Hellwig <hch@xxxxxx>
    Link: https://lore.kernel.org/r/20240911132954.5874-1-riyandhiman14@xxxxxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 00fb271a60510..0d1fe2b42b855 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -590,9 +590,11 @@ static bool blk_add_partition(struct gendisk *disk,
 
 	part = add_partition(disk, p, from, size, state->parts[p].flags,
 			     &state->parts[p].info);
-	if (IS_ERR(part) && PTR_ERR(part) != -ENXIO) {
-		printk(KERN_ERR " %s: p%d could not be added: %pe\n",
-		       disk->disk_name, p, part);
+	if (IS_ERR(part)) {
+		if (PTR_ERR(part) != -ENXIO) {
+			printk(KERN_ERR " %s: p%d could not be added: %pe\n",
+			       disk->disk_name, p, part);
+		}
 		return true;
 	}