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| author | Antonio Borneo <antonio.borneo@foss.st.com> | 2022-07-19 14:28:31 +0200 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2022-07-21 15:32:52 +0200 |
| commit | e3c8d33e0d62175c31ca7ab7ab01b18f0b6318d3 (patch) | |
| tree | 6e2693311ac5b129dfaf3fb80b142d70498f2c81 /scripts/gdb/linux/utils.py | |
| parent | 9a3bfa01aa1c5b5478edaf7c76ea0b3a94f9c13e (diff) | |
| download | lwn-e3c8d33e0d62175c31ca7ab7ab01b18f0b6318d3.tar.gz lwn-e3c8d33e0d62175c31ca7ab7ab01b18f0b6318d3.zip | |
scripts/gdb: fix 'lx-dmesg' on 32 bits arch
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
Diffstat (limited to 'scripts/gdb/linux/utils.py')
| -rw-r--r-- | scripts/gdb/linux/utils.py | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/scripts/gdb/linux/utils.py b/scripts/gdb/linux/utils.py index ff7c1799d588..1553f68716cc 100644 --- a/scripts/gdb/linux/utils.py +++ b/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 |