From: Rohan McLure Date: Mon, 6 Feb 2023 02:17:58 +0000 (+1100) Subject: powerpc/kcsan: Exclude udelay to prevent recursive instrumentation X-Git-Tag: baikal/mips/sdk6.1~213 X-Git-Url: https://git.baikalelectronics.ru/?a=commitdiff_plain;h=7cab1548ae2488966e4cc0dc30b6215b97a4e202;p=kernel.git powerpc/kcsan: Exclude udelay to prevent recursive instrumentation [ Upstream commit a182728806b796ce72488b8772a8a85684321a16 ] In order for KCSAN to increase its likelihood of observing a data race, it sets a watchpoint on memory accesses and stalls, allowing for detection of conflicting accesses by other kernel threads or interrupts. Stalls are implemented by injecting a call to udelay in instrumented code. To prevent recursive instrumentation, exclude udelay from being instrumented. Signed-off-by: Rohan McLure Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230206021801.105268-3-rmclure@linux.ibm.com Signed-off-by: Sasha Levin --- diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index f157552d79b38..285159e65a3ba 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -374,7 +374,7 @@ void vtime_flush(struct task_struct *tsk) #define calc_cputime_factors() #endif -void __delay(unsigned long loops) +void __no_kcsan __delay(unsigned long loops) { unsigned long start; @@ -395,7 +395,7 @@ void __delay(unsigned long loops) } EXPORT_SYMBOL(__delay); -void udelay(unsigned long usecs) +void __no_kcsan udelay(unsigned long usecs) { __delay(tb_ticks_per_usec * usecs); }