On Sun, Jul 16, 2023 at 09:07:14AM +0800, Chao Yu wrote:
> struct poll_wqueues table caused the stack usage of do_sys_poll() to
> grow beyond the warning limit on 32-bit architectures w/ gcc.
>
> fs/select.c: In function ‘do_sys_poll’:
> fs/select.c:1053:1: warning: the frame size of 1328 bytes is larger than 1024 bytes [-Wframe-larger-than=]
That seems particularly high. But it's only 604 bytes, so half of the
stack frame:
struct poll_wqueues {
poll_table pt; /* 0 8 */
struct poll_table_page * table; /* 8 4 */
struct task_struct * polling_task; /* 12 4 */
int triggered; /* 16 4 */
int error; /* 20 4 */
int inline_index; /* 24 4 */
struct poll_table_entry inline_entries[18]; /* 28 576 */
/* size: 604, cachelines: 10, members: 7 */
/* last cacheline: 28 bytes */
};
Also, you can see it's deliberately sized to fit on the stack (see
include/linux/poll.h). So you're completely destroying that optimisation.
You need to figure out why the stack is now so big. This isn't the
right solution.
