Hi David,
On Mon, 25 Aug 2025 at 14:07, David Laight david.laight.linux@gmail.com wrote:
On Mon, 25 Aug 2025 15:46:42 +0800 Lance Yang lance.yang@linux.dev wrote:
On 2025/8/25 14:17, Finn Thain wrote:
On Mon, 25 Aug 2025, Lance Yang wrote:
What if we squash the runtime check fix into your patch?
Did my patch not solve the problem?
Hmm... it should solve the problem for natural alignment, which is a critical fix.
But it cannot solve the problem of forced misalignment from drivers using #pragma pack(1). The runtime warning will still trigger in those cases.
I built a simple test module on a kernel with your patch applied:
#include <linux/module.h> #include <linux/init.h> struct __attribute__((packed)) test_container { char padding[49]; struct mutex io_lock; }; static int __init alignment_init(void) { struct test_container cont; pr_info("io_lock address offset mod 4: %lu\n", (unsigned long)&cont.io_lock % 4);Doesn't that give a compilation warning from 'taking the address of a packed member'? Ignore that at your peril.
More problematic is that, IIRC, m68k kmalloc() allocates 16bit aligned memory. This has broken other things in the past.
Really? AFAIK it always returns memory that is at least aligned to the cache line size (i.e. 16 bytes on m68k). So perhaps you are confusing "16bit" with "16byte"?
Gr{oetje,eeting}s,
Geert