From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: kasan, arm64: print report from tag fault handler Add error reporting for hardware tag-based KASAN. When CONFIG_KASAN_HW_TAGS is enabled, print KASAN report from the arm64 tag fault handler. SAS bits aren't set in ESR for all faults reported in EL1, so it's impossible to find out the size of the access the caused the fault. Adapt KASAN reporting code to handle this case. Link: https://lkml.kernel.org/r/b559c82b6a969afedf53b4694b475f0234067a1a.1606161801.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Co-developed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx> Tested-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx> Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/mm/fault.c | 14 ++++++++++++++ mm/kasan/report.c | 11 ++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-) --- a/arch/arm64/mm/fault.c~kasan-arm64-print-report-from-tag-fault-handler +++ a/arch/arm64/mm/fault.c @@ -14,6 +14,7 @@ #include <linux/mm.h> #include <linux/hardirq.h> #include <linux/init.h> +#include <linux/kasan.h> #include <linux/kprobes.h> #include <linux/uaccess.h> #include <linux/page-flags.h> @@ -297,10 +298,23 @@ static void die_kernel_fault(const char do_exit(SIGKILL); } +#ifdef CONFIG_KASAN_HW_TAGS static void report_tag_fault(unsigned long addr, unsigned int esr, struct pt_regs *regs) { + bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0; + + /* + * SAS bits aren't set for all faults reported in EL1, so we can't + * find out access size. + */ + kasan_report(addr, 0, is_write, regs->pc); } +#else +/* Tag faults aren't enabled without CONFIG_KASAN_HW_TAGS. */ +static inline void report_tag_fault(unsigned long addr, unsigned int esr, + struct pt_regs *regs) { } +#endif static void do_tag_recovery(unsigned long addr, unsigned int esr, struct pt_regs *regs) --- a/mm/kasan/report.c~kasan-arm64-print-report-from-tag-fault-handler +++ a/mm/kasan/report.c @@ -62,9 +62,14 @@ static void print_error_description(stru { pr_err("BUG: KASAN: %s in %pS\n", get_bug_type(info), (void *)info->ip); - pr_err("%s of size %zu at addr %px by task %s/%d\n", - info->is_write ? "Write" : "Read", info->access_size, - info->access_addr, current->comm, task_pid_nr(current)); + if (info->access_size) + pr_err("%s of size %zu at addr %px by task %s/%d\n", + info->is_write ? "Write" : "Read", info->access_size, + info->access_addr, current->comm, task_pid_nr(current)); + else + pr_err("%s at addr %px by task %s/%d\n", + info->is_write ? "Write" : "Read", + info->access_addr, current->comm, task_pid_nr(current)); } static DEFINE_SPINLOCK(report_lock); _
