From 3c7e842571a79ecc69ee3871849a95d202161c78 Mon Sep 17 00:00:00 2001 From: Fabian Vogt Date: Thu, 5 Oct 2023 15:57:44 +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 Reviewed-by: Daniel Kiper Reviewed-by: Qu Wenruo --- 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;