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| author | Peter Collingbourne <pcc@google.com> | 2021-06-03 02:52:30 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2021-06-04 21:32:21 +0300 |
| commit | c275c5c6d50a0518cdb0584e85905d10e7cefc6e (patch) | |
| tree | b621c3297979537bc51d124dbf57ebc932b98ca2 /include/trace/events/mmflags.h | |
| parent | 013bb59dbb7cf876449df860946458a595a96d51 (diff) | |
| download | linux-c275c5c6d50a0518cdb0584e85905d10e7cefc6e.tar.xz | |
kasan: disable freed user page poisoning with HW tags
Poisoning freed pages protects against kernel use-after-free. The
likelihood of such a bug involving kernel pages is significantly higher
than that for user pages. At the same time, poisoning freed pages can
impose a significant performance cost, which cannot always be justified
for user pages given the lower probability of finding a bug. Therefore,
disable freed user page poisoning when using HW tags. We identify
"user" pages via the flag set GFP_HIGHUSER_MOVABLE, which indicates
a strong likelihood of not being directly accessible to the kernel.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://linux-review.googlesource.com/id/I716846e2de8ef179f44e835770df7e6307be96c9
Link: https://lore.kernel.org/r/20210602235230.3928842-5-pcc@google.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'include/trace/events/mmflags.h')
| -rw-r--r-- | include/trace/events/mmflags.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index 629c7a0eaff2..390270e00a1d 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -85,6 +85,12 @@ #define IF_HAVE_PG_ARCH_2(flag,string) #endif +#ifdef CONFIG_KASAN_HW_TAGS +#define IF_HAVE_PG_SKIP_KASAN_POISON(flag,string) ,{1UL << flag, string} +#else +#define IF_HAVE_PG_SKIP_KASAN_POISON(flag,string) +#endif + #define __def_pageflag_names \ {1UL << PG_locked, "locked" }, \ {1UL << PG_waiters, "waiters" }, \ @@ -112,7 +118,8 @@ IF_HAVE_PG_UNCACHED(PG_uncached, "uncached" ) \ IF_HAVE_PG_HWPOISON(PG_hwpoison, "hwpoison" ) \ IF_HAVE_PG_IDLE(PG_young, "young" ) \ IF_HAVE_PG_IDLE(PG_idle, "idle" ) \ -IF_HAVE_PG_ARCH_2(PG_arch_2, "arch_2" ) +IF_HAVE_PG_ARCH_2(PG_arch_2, "arch_2" ) \ +IF_HAVE_PG_SKIP_KASAN_POISON(PG_skip_kasan_poison, "skip_kasan_poison") #define show_page_flags(flags) \ (flags) ? __print_flags(flags, "|", \ |