When going through our initialization code (init_espfix_ap() ) we need to keep in mind IRQs are off, and we need to handle it appropriately:
- Do not allocate with __GFP_FS. - No point in using a mutex. Signed-off-by: Sasha Levin <[email protected]> --- arch/x86/kernel/espfix_64.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c index 6afbb16..3ef78ce 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -64,7 +64,7 @@ DEFINE_PER_CPU_READ_MOSTLY(unsigned long, espfix_stack); DEFINE_PER_CPU_READ_MOSTLY(unsigned long, espfix_waddr); /* Initialization mutex - should this be a spinlock? */ -static DEFINE_MUTEX(espfix_init_mutex); +static DEFINE_SPINLOCK(espfix_init_mutex); /* Page allocation bitmap - each page serves ESPFIX_STACKS_PER_PAGE CPUs */ #define ESPFIX_MAX_PAGES DIV_ROUND_UP(CONFIG_NR_CPUS, ESPFIX_STACKS_PER_PAGE) @@ -161,7 +161,7 @@ void init_espfix_ap(void) if (likely(stack_page)) goto done; - mutex_lock(&espfix_init_mutex); + spin_lock(&espfix_init_mutex); /* Did we race on the lock? */ stack_page = ACCESS_ONCE(espfix_pages[page]); @@ -191,7 +191,7 @@ void init_espfix_ap(void) } pte_p = pte_offset_kernel(&pmd, addr); - stack_page = (void *)__get_free_page(GFP_KERNEL); + stack_page = (void *)__get_free_page(GFP_ATOMIC); pte = __pte(__pa(stack_page) | (__PAGE_KERNEL_RO & ptemask)); paravirt_alloc_pte(&init_mm, __pa(stack_page) >> PAGE_SHIFT); for (n = 0; n < ESPFIX_PTE_CLONES; n++) @@ -201,7 +201,7 @@ void init_espfix_ap(void) ACCESS_ONCE(espfix_pages[page]) = stack_page; unlock_done: - mutex_unlock(&espfix_init_mutex); + spin_unlock(&espfix_init_mutex); done: this_cpu_write(espfix_stack, addr); this_cpu_write(espfix_waddr, (unsigned long)stack_page -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
