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=]
Allocating dynamic memory in do_sys_poll() to fix this issue.
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
fs/select.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/fs/select.c b/fs/select.c
index 1b729494b4e9..2b9db5c938d9 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -982,7 +982,7 @@ static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
struct timespec64 *end_time)
{
- struct poll_wqueues table;
+ struct poll_wqueues *table;
int err = -EFAULT, fdcount, len;
/* Allocate small arguments on the stack to save memory and be
faster - use long to make sure the buffer is aligned properly
@@ -992,8 +992,14 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
struct poll_list *walk = head;
unsigned long todo = nfds;
- if (nfds > rlimit(RLIMIT_NOFILE))
- return -EINVAL;
+ table = kmalloc(sizeof(struct poll_wqueues), GFP_KERNEL);
+ if (!table)
+ return -ENOMEM;
+
+ if (nfds > rlimit(RLIMIT_NOFILE)) {
+ err = -EINVAL;
+ goto out_table;
+ }
len = min_t(unsigned int, nfds, N_STACK_PPS);
for (;;) {
@@ -1019,9 +1025,9 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
}
}
- poll_initwait(&table);
- fdcount = do_poll(head, &table, end_time);
- poll_freewait(&table);
+ poll_initwait(table);
+ fdcount = do_poll(head, table, end_time);
+ poll_freewait(table);
if (!user_write_access_begin(ufds, nfds * sizeof(*ufds)))
goto out_fds;
@@ -1043,7 +1049,8 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
walk = walk->next;
kfree(pos);
}
-
+out_table:
+ kfree(table);
return err;
Efault:
--
2.40.1
