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| author |   Qian Cai <cai@lca.pw> | 2018-12-07 17:34:49 -0500 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2018-12-10 17:53:12 +0000 |
| commit | 6e8830674ea77f57d57a33cca09083b117a71f41 (patch) | |
| tree | 895d981d2e466332c8d8691abf97966c9ff01e1c | |
| parent | arm64: Fix minor issues with the dcache_by_line_op macro (diff) | |
| download | linux-dev-6e8830674ea77f57d57a33cca09083b117a71f41.tar.xz linux-dev-6e8830674ea77f57d57a33cca09083b117a71f41.zip | |
arm64: kasan: Increase stack size for KASAN_EXTRA
If the kernel is configured with KASAN_EXTRA, the stack size is
increased significantly due to setting the GCC -fstack-reuse option to
"none" [1]. As a result, it can trigger a stack overrun quite often with
32k stack size compiled using GCC 8. For example, this reproducer
https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/madvise/madvise06.c
can trigger a "corrupted stack end detected inside scheduler" very
reliably with CONFIG_SCHED_STACK_END_CHECK enabled. There are other
reports at:
https://lore.kernel.org/lkml/1542144497.12945.29.camel@gmx.us/
https://lore.kernel.org/lkml/721E7B42-2D55-4866-9C1A-3E8D64F33F9C@gmx.us/
There are just too many functions that could have a large stack with
KASAN_EXTRA due to large local variables that have been called over and
over again without being able to reuse the stacks. Some noticiable ones
are,
size
7536 shrink_inactive_list
7440 shrink_page_list
6560 fscache_stats_show
3920 jbd2_journal_commit_transaction
3216 try_to_unmap_one
3072 migrate_page_move_mapping
3584 migrate_misplaced_transhuge_page
3920 ip_vs_lblcr_schedule
4304 lpfc_nvme_info_show
3888 lpfc_debugfs_nvmestat_data.constprop
There are other 49 functions over 2k in size while compiling kernel with
"-Wframe-larger-than=" on this machine. Hence, it is too much work to
change Makefiles for each object to compile without
-fsanitize-address-use-after-scope individually.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715#c23
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Will Deacon <will.deacon@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index b96442960aea..56562ff01076 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -76,12 +76,17 @@ /* * KASAN requires 1/8th of the kernel virtual address space for the shadow * region. KASAN can bloat the stack significantly, so double the (minimum) - * stack size when KASAN is in use. + * stack size when KASAN is in use, and then double it again if KASAN_EXTRA is + * on. */ #ifdef CONFIG_KASAN #define KASAN_SHADOW_SCALE_SHIFT 3 #define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT)) +#ifdef CONFIG_KASAN_EXTRA +#define KASAN_THREAD_SHIFT 2 +#else #define KASAN_THREAD_SHIFT 1 +#endif /* CONFIG_KASAN_EXTRA */ #else #define KASAN_SHADOW_SIZE (0) #define KASAN_THREAD_SHIFT 0 |