From: Aneesh Kumar K.V Date: Fri, 6 Nov 2015 02:50:51 +0000 (-0800) Subject: mm/kasan: prevent deadlock in kasan reporting X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=fc5aeeaf593278f07ffa4d97296e27423ecae867;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git mm/kasan: prevent deadlock in kasan reporting When we end up calling kasan_report in real mode, our shadow mapping for the spinlock variable will show poisoned. This will result in us calling kasan_report_error with lock_report spin lock held. To prevent this disable kasan reporting when we are priting error w.r.t kasan. Signed-off-by: Aneesh Kumar K.V Reviewed-by: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/kasan/report.c b/mm/kasan/report.c index c5367089703c..7833f074ede8 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -173,12 +173,10 @@ static void print_shadow_for_address(const void *addr) * function, because generic functions may try to * access kasan mapping for the passed address. */ - kasan_disable_current(); memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW); print_hex_dump(KERN_ERR, buffer, DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1, shadow_buf, SHADOW_BYTES_PER_ROW, 0); - kasan_enable_current(); if (row_is_guilty(shadow_row, shadow)) pr_err("%*c\n", @@ -195,6 +193,10 @@ void kasan_report_error(struct kasan_access_info *info) { unsigned long flags; + /* + * Make sure we don't end up in loop. + */ + kasan_disable_current(); spin_lock_irqsave(&report_lock, flags); pr_err("=================================" "=================================\n"); @@ -204,12 +206,17 @@ void kasan_report_error(struct kasan_access_info *info) pr_err("=================================" "=================================\n"); spin_unlock_irqrestore(&report_lock, flags); + kasan_enable_current(); } void kasan_report_user_access(struct kasan_access_info *info) { unsigned long flags; + /* + * Make sure we don't end up in loop. + */ + kasan_disable_current(); spin_lock_irqsave(&report_lock, flags); pr_err("=================================" "=================================\n"); @@ -222,6 +229,7 @@ void kasan_report_user_access(struct kasan_access_info *info) pr_err("=================================" "=================================\n"); spin_unlock_irqrestore(&report_lock, flags); + kasan_enable_current(); } void kasan_report(unsigned long addr, size_t size,