Commit e82b3a63 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Kent Overstreet
Browse files

bcachefs: ioctl: avoid stack overflow warning 



Multiple ioctl handlers individually use a lot of stack space, and clang chooses
to inline them into the bch2_fs_ioctl() function, blowing through the warning
limit:

fs/bcachefs/chardev.c:655:6: error: stack frame size (1032) exceeds limit (1024) in 'bch2_fs_ioctl' [-Werror,-Wframe-larger-than]
  655 | long bch2_fs_ioctl(struct bch_fs *c, unsigned cmd, void __user *arg)

By marking the largest two of them as noinline_for_stack, no indidual code path
ends up using this much, which avoids the warning and reduces the possible
total stack usage in the ioctl handler.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent c3dd2531

fs/bcachefs/chardev.c

+2 −2
Original line number Diff line number Diff line
@@ -399,7 +399,7 @@ static long bch2_ioctl_data(struct bch_fs *c, 
	return ret;

}



static long bch2_ioctl_fs_usage(struct bch_fs *c,

static noinline_for_stack long bch2_ioctl_fs_usage(struct bch_fs *c,

				struct bch_ioctl_fs_usage __user *user_arg)

{

	struct bch_ioctl_fs_usage arg = {};
@@ -469,7 +469,7 @@ static long bch2_ioctl_query_accounting(struct bch_fs *c, 
}



/* obsolete, didn't allow for new data types: */

static long bch2_ioctl_dev_usage(struct bch_fs *c,

static noinline_for_stack long bch2_ioctl_dev_usage(struct bch_fs *c,

				 struct bch_ioctl_dev_usage __user *user_arg)

{

	struct bch_ioctl_dev_usage arg;