Messages in this thread | | | From | Guenter Roeck <> | Subject | Re: [PATCH] riscv: Disable STACKPROTECTOR_PER_TASK if GCC_PLUGIN_RANDSTRUCT is enabled | Date | Fri, 23 Jul 2021 19:13:47 -0700 |
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On 7/23/21 5:58 PM, Palmer Dabbelt wrote: > On Tue, 06 Jul 2021 09:26:21 PDT (-0700), linux@roeck-us.net wrote: >> riscv uses the value of TSK_STACK_CANARY to set >> stack-protector-guard-offset. With GCC_PLUGIN_RANDSTRUCT enabled, that >> value is non-deterministic, and with riscv:allmodconfig often results >> in build errors such as >> >> cc1: error: '8120' is not a valid offset in '-mstack-protector-guard-offset=' >> >> Enable STACKPROTECTOR_PER_TASK only if GCC_PLUGIN_RANDSTRUCT is disabled >> to fix the problem. >> >> Fixes: fea2fed201ee5 ("riscv: Enable per-task stack canaries") >> Cc: Guo Ren <guoren@linux.alibaba.com> >> Signed-off-by: Guenter Roeck <linux@roeck-us.net> >> --- >> arch/riscv/Kconfig | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig >> index 469a70bd8da6..3afb84fa2190 100644 >> --- a/arch/riscv/Kconfig >> +++ b/arch/riscv/Kconfig >> @@ -486,6 +486,7 @@ config CC_HAVE_STACKPROTECTOR_TLS >> >> config STACKPROTECTOR_PER_TASK >> def_bool y >> + depends on !GCC_PLUGIN_RANDSTRUCT >> depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS >> >> config PHYS_RAM_BASE_FIXED > > Thanks, this is on fixes. I do an allmodconfig build and haven't seen these failures, is there something special I need to do to get this working? I know nothing about GCC plugins...
The problem is seen only randomly. It depends on the value of TSK_STACK_CANARY in include/generated/asm-offsets.h. That in turn depends on the location of stack_canary in struct task_struct. You may have to try several times from a clean tree to see the problem.
Guenter
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