diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2024-02-12 17:42:44 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2024-02-14 14:24:06 +1100 |
| commit | f1acb109505d983779bbb7e20a1ee6244d2b5736 (patch) | |
| tree | f611682610286749a78659c134144b9603460f3c | |
| parent | 1fba2bf8e9d5a27b7394856181b6200de7260b79 (diff) | |
powerpc/kasan: Limit KASAN thread size increase to 32KB
KASAN is seen to increase stack usage, to the point that it was reported
to lead to stack overflow on some 32-bit machines (see link).
To avoid overflows the stack size was doubled for KASAN builds in
commit 3e8635fb2e07 ("powerpc/kasan: Force thread size increase with
KASAN").
However with a 32KB stack size to begin with, the doubling leads to a
64KB stack, which causes build errors:
arch/powerpc/kernel/switch.S:249: Error: operand out of range (0x000000000000fe50 is not between 0xffffffffffff8000 and 0x0000000000007fff)
Although the asm could be reworked, in practice a 32KB stack seems
sufficient even for KASAN builds - the additional usage seems to be in
the 2-3KB range for a 64-bit KASAN build.
So only increase the stack for KASAN if the stack size is < 32KB.
Fixes: 18f14afe2816 ("powerpc/64s: Increase default stack size to 32KB")
Reported-by: Spoorthy <spoorthy@linux.ibm.com>
Reported-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Benjamin Gray <bgray@linux.ibm.com>
Link: https://lore.kernel.org/linuxppc-dev/bug-207129-206035@https.bugzilla.kernel.org%2F/
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240212064244.3924505-1-mpe@ellerman.id.au
| -rw-r--r-- | arch/powerpc/include/asm/thread_info.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index bf5dde1a4114..15c5691dd218 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -14,7 +14,7 @@ #ifdef __KERNEL__ -#ifdef CONFIG_KASAN +#if defined(CONFIG_KASAN) && CONFIG_THREAD_SHIFT < 15 #define MIN_THREAD_SHIFT (CONFIG_THREAD_SHIFT + 1) #else #define MIN_THREAD_SHIFT CONFIG_THREAD_SHIFT |