From fce0128863b22dd6d9a4e5383645ac70656970a7 Mon Sep 17 00:00:00 2001 From: Benjamin Berg Date: Sun, 3 Nov 2024 16:05:02 +0100 Subject: [PATCH] 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 Link: https://patch.msgid.link/20241103150506.1367695-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg --- arch/um/os-Linux/mem.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c index 857e3deab293..72f302f4d197 100644 --- a/arch/um/os-Linux/mem.c +++ b/arch/um/os-Linux/mem.c @@ -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. */ -- 2.50.1