From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Mon, 31 Mar 2025 20:19:04 +0000 (-0400)
Subject: bcachefs: Fix null ptr deref in bch2_write_endio()
X-Git-Tag: v6.15-rc1~31^2~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=de399658588931506e1b3f4cc63cb3c9134a692e;p=thirdparty%2Fkernel%2Fstable.git

bcachefs: Fix null ptr deref in bch2_write_endio()

This was previously hard to hit since it requires racing with device
removal, but splitting up io_ref uncovered it.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---

diff --git a/fs/bcachefs/io_write.c b/fs/bcachefs/io_write.c
index 07b55839768ea..0503ac1952cd0 100644
--- a/fs/bcachefs/io_write.c
+++ b/fs/bcachefs/io_write.c
@@ -697,12 +697,19 @@ static void bch2_write_endio(struct bio *bio)
 	bch2_account_io_completion(ca, BCH_MEMBER_ERROR_write,
 				   wbio->submit_time, !bio->bi_status);
 
-	if (bio->bi_status) {
-		bch_err_inum_offset_ratelimited(ca,
-				    op->pos.inode,
-				    wbio->inode_offset << 9,
-				    "data write error: %s",
-				    bch2_blk_status_to_str(bio->bi_status));
+	if (unlikely(bio->bi_status)) {
+		if (ca)
+			bch_err_inum_offset_ratelimited(ca,
+					    op->pos.inode,
+					    wbio->inode_offset << 9,
+					    "data write error: %s",
+					    bch2_blk_status_to_str(bio->bi_status));
+		else
+			bch_err_inum_offset_ratelimited(c,
+					    op->pos.inode,
+					    wbio->inode_offset << 9,
+					    "data write error: %s",
+					    bch2_blk_status_to_str(bio->bi_status));
 		set_bit(wbio->dev, op->failed.d);
 		op->flags |= BCH_WRITE_io_error;
 	}