From f903b9a9adb64e733e581771d2a24efae7fbe529 Mon Sep 17 00:00:00 2001 From: Fabian Vogt Date: Thu, 5 Oct 2023 11:02:25 +0200 Subject: [PATCH] fs/btrfs: Zero file data not backed by extents Implicit holes in file data need to be zeroed explicitly, instead of just leaving the data in the buffer uninitialized. This led to kernels randomly failing to boot in "fun" ways when loaded from btrfs with the no_holes feature enabled, because large blocks of zeros in the kernel file contained random data instead. Signed-off-by: Fabian Vogt --- grub-core/fs/btrfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index 19bff4610..ba0c58352 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -1603,6 +1603,8 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data, csize = grub_le_to_cpu64 (key_out.offset) - pos; if (csize > len) csize = len; + + grub_memset (buf, 0, csize); buf += csize; pos += csize; len -= csize; -- 2.42.0