From 6046a3bed1c2b028e692f7606e3450d1c93e8fdd Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 10 Jun 2025 11:21:50 +0200 Subject: [PATCH] lib/test_hmm: reduce stack usage The various test ioctl handlers use arrays of 64 integers that add up to 1KiB of stack data, which in turn leads to exceeding the warning limit in some configurations: lib/test_hmm.c:935:12: error: stack frame size (1408) exceeds limit (1280) in 'dmirror_migrate_to_device' [-Werror,-Wframe-larger-than] Use half the size for these arrays, in order to stay under the warning limits. The code can already deal with arbitrary lengths, but this may be a little less efficient. Link: https://lkml.kernel.org/r/20250610092159.2639515-1-arnd@kernel.org Signed-off-by: Arnd Bergmann Cc: Alistair Popple Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Jeff Johnson Cc: Jerome Glisse Cc: Thorsten Blum Signed-off-by: Andrew Morton --- lib/test_hmm.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 5b144bc5c4ec7..761725bc713cd 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -330,7 +330,7 @@ static int dmirror_fault(struct dmirror *dmirror, unsigned long start, { struct mm_struct *mm = dmirror->notifier.mm; unsigned long addr; - unsigned long pfns[64]; + unsigned long pfns[32]; struct hmm_range range = { .notifier = &dmirror->notifier, .hmm_pfns = pfns, @@ -879,8 +879,8 @@ static int dmirror_migrate_to_system(struct dmirror *dmirror, unsigned long size = cmd->npages << PAGE_SHIFT; struct mm_struct *mm = dmirror->notifier.mm; struct vm_area_struct *vma; - unsigned long src_pfns[64] = { 0 }; - unsigned long dst_pfns[64] = { 0 }; + unsigned long src_pfns[32] = { 0 }; + unsigned long dst_pfns[32] = { 0 }; struct migrate_vma args = { 0 }; unsigned long next; int ret; @@ -939,8 +939,8 @@ static int dmirror_migrate_to_device(struct dmirror *dmirror, unsigned long size = cmd->npages << PAGE_SHIFT; struct mm_struct *mm = dmirror->notifier.mm; struct vm_area_struct *vma; - unsigned long src_pfns[64] = { 0 }; - unsigned long dst_pfns[64] = { 0 }; + unsigned long src_pfns[32] = { 0 }; + unsigned long dst_pfns[32] = { 0 }; struct dmirror_bounce bounce; struct migrate_vma args = { 0 }; unsigned long next; @@ -1144,8 +1144,8 @@ static int dmirror_snapshot(struct dmirror *dmirror, unsigned long size = cmd->npages << PAGE_SHIFT; unsigned long addr; unsigned long next; - unsigned long pfns[64]; - unsigned char perm[64]; + unsigned long pfns[32]; + unsigned char perm[32]; char __user *uptr; struct hmm_range range = { .hmm_pfns = pfns, -- 2.47.2