Commit fce01288 authored Nov 03, 2024 by Benjamin Berg Committed by Johannes Berg Nov 07, 2024

um: set DONTDUMP and DONTFORK flags on KASAN shadow memory



There is no point in either dumping the KASAN shadow memory or doing
copy-on-write after a fork on these memory regions.

This considerably speeds up coredump generation.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-1-benjamin@sipsolutions.net


Signed-off-by: Johannes Berg <johannes.berg@intel.com>

parent 81e0679d

arch/um/os-Linux/mem.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,18 @@ void kasan_map_memory(void *start, size_t len)
		strerror(errno));
		exit(1);
		}

		if (madvise(start, len, MADV_DONTDUMP)) {
		os_info("Couldn't set MAD_DONTDUMP on shadow memory: %s\n.",
		strerror(errno));
		exit(1);
		}

		if (madvise(start, len, MADV_DONTFORK)) {
		os_info("Couldn't set MADV_DONTFORK on shadow memory: %s\n.",
		strerror(errno));
		exit(1);
		}
		}

		/* Set by make_tempfile() during early boot. */