scripts/gdb: fix 'lx-dmesg' on 32 bits arch
[ Upstream commit e3c8d33e0d62175c31ca7ab7ab01b18f0b6318d3 ]
The type atomic_long_t can have size 4 or 8 bytes, depending on
CONFIG_64BIT; it's only content, the field 'counter', is either an
int or a s64 value.
Current code incorrectly uses the fixed size utils.read_u64() to
read the field 'counter' inside atomic_long_t.
On 32 bits architectures reading the last element 'tail_id' of the
struct prb_desc_ring:
struct prb_desc_ring {
...
atomic_long_t tail_id;
};
causes the utils.read_u64() to access outside the boundary of the
struct and the gdb command 'lx-dmesg' exits with error:
Python Exception <class 'IndexError'>: index out of range
Error occurred in Python: index out of range
Query the really used atomic_long_t counter type size.
Link: https://lore.kernel.org/r/20220617143758.137307-1-antonio.borneo@foss.st.com
Fixes: e60768311af8 ("scripts/gdb: update for lockless printk ringbuffer")
Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
[pmladek@suse.com: Query the really used atomic_long_t counter type size]
Tested-by: Antonio Borneo <antonio.borneo@foss.st.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220719122831.19890-1-pmladek@suse.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/scripts/gdb/linux/utils.py b/scripts/gdb/linux/utils.py
index ff7c179..1553f68 100644
--- a/scripts/gdb/linux/utils.py
+++ b/scripts/gdb/linux/utils.py
@@ -35,13 +35,12 @@
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 @@
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