[PATCH mm v11 38/42] kasan, arm64: print report from tag fault handler
From: Andrey Konovalov <hidden>
Date: 2020-11-23 20:12:41
Also in:
linux-mm, lkml
Subsystem:
arm64 port (aarch64 architecture), kasan, memory management, the rest · Maintainers:
Catalin Marinas, Will Deacon, Andrey Ryabinin, Andrew Morton, Linus Torvalds
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. Signed-off-by: Andrey Konovalov <redacted> Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Alexander Potapenko <glider@google.com> --- Change-Id: I3780fe7db6e075dff2937d3d8508f55c9322b095 --- arch/arm64/mm/fault.c | 14 ++++++++++++++ mm/kasan/report.c | 11 ++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 1e4b9353c68a..3aac2e72f81e 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c@@ -15,6 +15,7 @@ #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>
@@ -298,10 +299,23 @@ static void die_kernel_fault(const char *msg, unsigned long addr, 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)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 2c503b667413..a69c2827a125 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c@@ -62,9 +62,14 @@ static void print_error_description(struct kasan_access_info *info) { 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);
--
2.29.2.454.gaff20da3a2-goog
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