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Resolve the issue of system crashes caused by using mutex locks for memory allocation when a thread polls multiple file descriptors #10592

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Resolve the issue of system crashes caused by using mutex locks for memory allocation when a thread polls multiple file descriptors #10592

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33 changes: 20 additions & 13 deletions components/libc/posix/io/poll/poll.c
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
* mechanism wakeup algorithm does not correctly distinguish
* the current wait state.
* 2024-03-29 TroyMitchelle Add all function comments and comments to structure members
* 2025-08-09 zhuhangjiang Resolve the issue of system crashes caused by using mutex locks for memory allocation when a thread polls multiple file descriptors.
*/

#include <stdint.h>
Expand All @@ -30,21 +31,23 @@ enum rt_poll_status
RT_POLL_STAT_WAITING /**< Poll operation waiting status. */
};

struct rt_poll_node
{
struct rt_wqueue_node wqn; /**< Wait queue node for the poll node. */
struct rt_poll_table *pt; /**< Pointer to the parent poll table. */
struct rt_poll_node *next; /**< Pointer to the next poll node. */
};

#define MAX_POLL_NODES 8

struct rt_poll_table
{
rt_pollreq_t req; /**< Poll request. */
enum rt_poll_status status; /**< Status of the poll operation. */
rt_thread_t polling_thread; /**< Polling thread associated with the table. */
struct rt_poll_node *nodes; /**< Linked list of poll nodes. */
};


struct rt_poll_node
{
struct rt_wqueue_node wqn; /**< Wait queue node for the poll node. */
struct rt_poll_table *pt; /**< Pointer to the parent poll table. */
struct rt_poll_node *next; /**< Pointer to the next poll node. */
struct rt_poll_node node_pool[MAX_POLL_NODES]; /**< poll_node */
int node_pool_used;
};

static RT_DEFINE_SPINLOCK(_spinlock);
Expand Down Expand Up @@ -95,12 +98,15 @@ static void _poll_add(rt_wqueue_t *wq, rt_pollreq_t *req)
struct rt_poll_table *pt;
struct rt_poll_node *node;

node = (struct rt_poll_node *)rt_malloc(sizeof(struct rt_poll_node));
if (node == RT_NULL)
return;

pt = rt_container_of(req, struct rt_poll_table, req);

if (pt->node_pool_used >= MAX_POLL_NODES)
{
printf("ERR:poll max is 8\n");
return;
}

node = &pt->node_pool[pt->node_pool_used++];
node->wqn.key = req->_key;
rt_list_init(&(node->wqn.list));
node->wqn.polling_thread = pt->polling_thread;
Expand All @@ -125,6 +131,7 @@ static void poll_table_init(struct rt_poll_table *pt)
pt->status = RT_POLL_STAT_INIT;
pt->nodes = RT_NULL;
pt->polling_thread = rt_thread_self();
pt->node_pool_used = 0;
}

/**
Expand Down Expand Up @@ -327,7 +334,7 @@ static void poll_teardown(struct rt_poll_table *pt)
node = next;
rt_wqueue_remove(&node->wqn);
next = node->next;
rt_free(node);
// rt_free(node);
}
}

Expand Down