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0c24ee770c
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>
(cherry picked from commit
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| .. | ||
| common.c | ||
| generic.c | ||
| hw_tags.c | ||
| init.c | ||
| kasan.h | ||
| Makefile | ||
| quarantine.c | ||
| report_generic.c | ||
| report_hw_tags.c | ||
| report_sw_tags.c | ||
| report.c | ||
| shadow.c | ||
| sw_tags.c | ||