The use of kmap_atomic() is being deprecated in favor of kmap_local_page(). With kmap_local_page(), the mappings are per thread, CPU local, not globally visible and can take page faults. Furthermore, the mappings can be acquired from any context (including interrupts). Therefore, use kmap_local_page() in copy_string_kernel() instead of kmap_atomic(). Tested with xfstests on a QEMU + KVM 32-bits VM booting a kernel with HIGHMEM64GB enabled. Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx> --- I sent a first patch to fs/exec.c for converting kmap() and kmap_atomic() to kmap_local_page(): https://lore.kernel.org/lkml/20220630163527.9776-1-fmdefrancesco@xxxxxxxxx/ Some days ago, Ira Weiny, while he was reviewing that patch, made me notice that I had overlooked a second kmap_atomic() in the same file (thanks): https://lore.kernel.org/lkml/YsiQptk19txHrG4c@iweiny-desk3/ I've been asked to send this as an additional change. This is why there will not be any second version of that previous patch. fs/exec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 4a2129c0d422..5fa652ca5823 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -639,11 +639,11 @@ int copy_string_kernel(const char *arg, struct linux_binprm *bprm) page = get_arg_page(bprm, pos, 1); if (!page) return -E2BIG; - kaddr = kmap_atomic(page); + kaddr = kmap_local_page(page); flush_arg_page(bprm, pos & PAGE_MASK, page); memcpy(kaddr + offset_in_page(pos), arg, bytes_to_copy); flush_dcache_page(page); - kunmap_atomic(kaddr); + kunmap_local(kaddr); put_arg_page(page); } -- 2.36.1
