kasan: split out print_report from __kasan_report

Split out the part of __kasan_report() that prints things into
print_report().  One of the subsequent patches makes another error handler
use print_report() as well.

Includes lower-level changes:

 - Allow addr_has_metadata() accepting a tagged address.

 - Drop the const qualifier from the fields of kasan_access_info to
   avoid excessive type casts.

 - Change the type of the address argument of __kasan_report() and
   end_report() to void * to reduce the number of type casts.

Link: https://lkml.kernel.org/r/9be3ed99dd24b9c4e1c4a848b69a0c6ecefd845e.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index cc7162a..40b863e 100644 (file)
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -128,8 +128,8 @@ static inline bool kasan_sync_fault_possible(void)
 #define META_ROWS_AROUND_ADDR 2
 
 struct kasan_access_info {
-       const void *access_addr;
-       const void *first_bad_addr;
+       void *access_addr;
+       void *first_bad_addr;
        size_t access_size;
        bool is_write;
        unsigned long ip;
@@ -239,7 +239,8 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
 
 static inline bool addr_has_metadata(const void *addr)
 {
-       return (addr >= kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
+       return (kasan_reset_tag(addr) >=
+               kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
 }
 
 /**

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 9286ff6..bb4c29b 100644 (file)
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -139,10 +139,11 @@ static void start_report(unsigned long *flags, bool sync)
        pr_err("==================================================================\n");
 }
 
-static void end_report(unsigned long *flags, unsigned long addr)
+static void end_report(unsigned long *flags, void *addr)
 {
        if (addr)
-               trace_error_report_end(ERROR_DETECTOR_KASAN, addr);
+               trace_error_report_end(ERROR_DETECTOR_KASAN,
+                                      (unsigned long)addr);
        pr_err("==================================================================\n");
        add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
        spin_unlock_irqrestore(&report_lock, *flags);
@@ -398,7 +399,7 @@ void kasan_report_invalid_free(void *object, unsigned long ip)
        pr_err("\n");
        print_address_description(object, tag);
        print_memory_metadata(object);
-       end_report(&flags, (unsigned long)object);
+       end_report(&flags, object);
 }
 
 #ifdef CONFIG_KASAN_HW_TAGS
@@ -411,44 +412,47 @@ void kasan_report_async(void)
        pr_err("Asynchronous mode enabled: no access details available\n");
        pr_err("\n");
        dump_stack_lvl(KERN_ERR);
-       end_report(&flags, 0);
+       end_report(&flags, NULL);
 }
 #endif /* CONFIG_KASAN_HW_TAGS */
 
-static void __kasan_report(unsigned long addr, size_t size, bool is_write,
+static void print_report(struct kasan_access_info *info)
+{
+       void *tagged_addr = info->access_addr;
+       void *untagged_addr = kasan_reset_tag(tagged_addr);
+       u8 tag = get_tag(tagged_addr);
+
+       print_error_description(info);
+       if (addr_has_metadata(untagged_addr))
+               kasan_print_tags(tag, info->first_bad_addr);
+       pr_err("\n");
+
+       if (addr_has_metadata(untagged_addr)) {
+               print_address_description(untagged_addr, tag);
+               print_memory_metadata(info->first_bad_addr);
+       } else {
+               dump_stack_lvl(KERN_ERR);
+       }
+}
+
+static void __kasan_report(void *addr, size_t size, bool is_write,
                                unsigned long ip)
 {
        struct kasan_access_info info;
-       void *tagged_addr;
-       void *untagged_addr;
        unsigned long flags;
 
        start_report(&flags, true);
 
-       tagged_addr = (void *)addr;
-       untagged_addr = kasan_reset_tag(tagged_addr);
-
-       info.access_addr = tagged_addr;
-       if (addr_has_metadata(untagged_addr))
-               info.first_bad_addr =
-                       kasan_find_first_bad_addr(tagged_addr, size);
+       info.access_addr = addr;
+       if (addr_has_metadata(addr))
+               info.first_bad_addr = kasan_find_first_bad_addr(addr, size);
        else
-               info.first_bad_addr = untagged_addr;
+               info.first_bad_addr = addr;
        info.access_size = size;
        info.is_write = is_write;
        info.ip = ip;
 
-       print_error_description(&info);
-       if (addr_has_metadata(untagged_addr))
-               kasan_print_tags(get_tag(tagged_addr), info.first_bad_addr);
-       pr_err("\n");
-
-       if (addr_has_metadata(untagged_addr)) {
-               print_address_description(untagged_addr, get_tag(tagged_addr));
-               print_memory_metadata(info.first_bad_addr);
-       } else {
-               dump_stack_lvl(KERN_ERR);
-       }
+       print_report(&info);
 
        end_report(&flags, addr);
 }
@@ -460,7 +464,7 @@ bool kasan_report(unsigned long addr, size_t size, bool is_write,
        bool ret = false;
 
        if (likely(report_enabled())) {
-               __kasan_report(addr, size, is_write, ip);
+               __kasan_report((void *)addr, size, is_write, ip);
                ret = true;
        }