coredump: reduce stack usage in vfs_coredump

A recent patch changed the coredump code in mostly harmless ways,
but after this I get a very high stack usage in one function
that was benign before:

fs/coredump.c: In function 'vfs_coredump':
fs/coredump.c:1313:1: error: the frame size of 1872 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

This happens reproducibly every couple of randconfig builds on
s390 with gcc-16 and seems to be caused by kasan checks causing
local variables to be spilled to the stack.

Marking the do_coredump function as noinline_for_stack avoids
the problem here, instead I get only 464 and 672 bytes in
the worst case for vfs_coredump and do_coredump, respectively.

Fixes: 3209535cd39e ("pidfs: record the coredump on the dumping thread's pid too")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20261016194650.1580988-1-arnd@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

0 files changed, 0 insertions, 0 deletions