Merge tag 'printk-for-5.20-sane' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Allow reading kernel log in gdb even on 32 bits systems

 - More granular check of the buffer usage in printf selftest

 - Clang warning fix

* tag 'printk-for-5.20-sane' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  lib/test_printf.c: fix clang -Wformat warnings
  scripts/gdb: fix 'lx-dmesg' on 32 bits arch
  lib/test_printf.c: split write-beyond-buffer check in two

lib/test_printf.c

@@ -30,6 +30,12 @@
 #define PAD_SIZE 16
 #define FILL_CHAR '$'
 
+#define NOWARN(option, comment, block) \
+	__diag_push(); \
+	__diag_ignore_all(#option, comment); \
+	block \
+	__diag_pop();
+
 KSTM_MODULE_GLOBALS();
 
 static char *test_buffer __initdata;
@@ -78,12 +84,17 @@ do_test(int bufsize, const char *expect, int elen,
 		return 1;
 	}
 
-	if (memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) {
+	if (memchr_inv(test_buffer + written + 1, FILL_CHAR, bufsize - (written + 1))) {
 		pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul-terminator\n",
 			bufsize, fmt);
 		return 1;
 	}
 
+	if (memchr_inv(test_buffer + bufsize, FILL_CHAR, BUF_SIZE + PAD_SIZE - bufsize)) {
+		pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond buffer\n", bufsize, fmt);
+		return 1;
+	}
+
 	if (memcmp(test_buffer, expect, written)) {
 		pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'\n",
 			bufsize, fmt, test_buffer, written, expect);
@@ -154,9 +165,11 @@ test_number(void)
 	test("0x1234abcd  ", "%#-12x", 0x1234abcd);
 	test("  0x1234abcd", "%#12x", 0x1234abcd);
 	test("0|001| 12|+123| 1234|-123|-1234", "%d|%03d|%3d|%+d|% d|%+d|% d", 0, 1, 12, 123, 1234, -123, -1234);
-	test("0|1|1|128|255", "%hhu|%hhu|%hhu|%hhu|%hhu", 0, 1, 257, 128, -1);
-	test("0|1|1|-128|-1", "%hhd|%hhd|%hhd|%hhd|%hhd", 0, 1, 257, 128, -1);
-	test("2015122420151225", "%ho%ho%#ho", 1037, 5282, -11627);
+	NOWARN(-Wformat, "Intentionally test narrowing conversion specifiers.", {
+		test("0|1|1|128|255", "%hhu|%hhu|%hhu|%hhu|%hhu", 0, 1, 257, 128, -1);
+		test("0|1|1|-128|-1", "%hhd|%hhd|%hhd|%hhd|%hhd", 0, 1, 257, 128, -1);
+		test("2015122420151225", "%ho%ho%#ho", 1037, 5282, -11627);
+	})
 	/*
 	 * POSIX/C99: »The result of converting zero with an explicit
 	 * precision of zero shall be no characters.« Hence the output

scripts/gdb/linux/dmesg.py

@@ -22,7 +22,6 @@ prb_desc_type = utils.CachedType("struct prb_desc")
 prb_desc_ring_type = utils.CachedType("struct prb_desc_ring")
 prb_data_ring_type = utils.CachedType("struct prb_data_ring")
 printk_ringbuffer_type = utils.CachedType("struct printk_ringbuffer")
-atomic_long_type = utils.CachedType("atomic_long_t")
 
 class LxDmesg(gdb.Command):
     """Print Linux kernel log buffer."""
@@ -68,8 +67,6 @@ class LxDmesg(gdb.Command):
         off = prb_data_ring_type.get_type()['data'].bitpos // 8
         text_data_addr = utils.read_ulong(text_data_ring, off)
 
-        counter_off = atomic_long_type.get_type()['counter'].bitpos // 8
-
         sv_off = prb_desc_type.get_type()['state_var'].bitpos // 8
 
         off = prb_desc_type.get_type()['text_blk_lpos'].bitpos // 8
@@ -89,9 +86,9 @@ class LxDmesg(gdb.Command):
 
         # read in tail and head descriptor ids
         off = prb_desc_ring_type.get_type()['tail_id'].bitpos // 8
-        tail_id = utils.read_u64(desc_ring, off + counter_off)
+        tail_id = utils.read_atomic_long(desc_ring, off)
         off = prb_desc_ring_type.get_type()['head_id'].bitpos // 8
-        head_id = utils.read_u64(desc_ring, off + counter_off)
+        head_id = utils.read_atomic_long(desc_ring, off)
 
         did = tail_id
         while True:
@@ -102,7 +99,7 @@ class LxDmesg(gdb.Command):
             desc = utils.read_memoryview(inf, desc_addr + desc_off, desc_sz).tobytes()
 
             # skip non-committed record
-            state = 3 & (utils.read_u64(desc, sv_off + counter_off) >> desc_flags_shift)
+            state = 3 & (utils.read_atomic_long(desc, sv_off) >> desc_flags_shift)
             if state != desc_committed and state != desc_finalized:
                 if did == head_id:
                     break

scripts/gdb/linux/utils.py

@@ -35,13 +35,12 @@ class CachedType:
 
 
 long_type = CachedType("long")
-
+atomic_long_type = CachedType("atomic_long_t")
 
 def get_long_type():
     global long_type
     return long_type.get_type()
 
-
 def offset_of(typeobj, field):
     element = gdb.Value(0).cast(typeobj)
     return int(str(element[field].address).split()[0], 16)
@@ -129,6 +128,17 @@ def read_ulong(buffer, offset):
     else:
         return read_u32(buffer, offset)
 
+atomic_long_counter_offset = atomic_long_type.get_type()['counter'].bitpos
+atomic_long_counter_sizeof = atomic_long_type.get_type()['counter'].type.sizeof
+
+def read_atomic_long(buffer, offset):
+    global atomic_long_counter_offset
+    global atomic_long_counter_sizeof
+
+    if atomic_long_counter_sizeof == 8:
+        return read_u64(buffer, offset + atomic_long_counter_offset)
+    else:
+        return read_u32(buffer, offset + atomic_long_counter_offset)
 
 target_arch = None