From: Zizhi Wo <wozizhi@huawei.com> hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IB5UKT -------------------------------- On demand loading mode in fscache_hash_cookie() have triggered softlockup. Following is the stack: fscache_hash_cookie hlist_bl_lock fscache_print_cookie pr_err printk ... console_unlock --continuous print data hlist_bl_unlock --not called Due to the slow transmission speed of the physical serial port and the large amount of data printing, printk will loop in console_unlock. So the process holds the lock and blocks others. To avoid similar problems, simply delete the fscache_print_cookie() as it is not necessary to print the internal state of the cookie. And replace pr_err() with pr_err_ratelimited() to limit its print speed. Fixes: ec0328e46d6e ("fscache: Maintain a catalogue of allocated cookies") Signed-off-by: Zizhi Wo <wozizhi@huawei.com> Signed-off-by: Baokun Li <libaokun1@huawei.com> --- fs/fscache/cookie.c | 30 +----------------------------- 1 file changed, 1 insertion(+), 29 deletions(-) diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index ea1beed4df11..66a4db1eee36 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -27,32 +27,6 @@ static int fscache_alloc_object(struct fscache_cache *cache, static int fscache_attach_object(struct fscache_cookie *cookie, struct fscache_object *object); -static void fscache_print_cookie(struct fscache_cookie *cookie, char prefix) -{ - struct hlist_node *object; - const u8 *k; - unsigned loop; - - pr_err("%c-cookie c=%p [p=%p fl=%lx nc=%u na=%u]\n", - prefix, cookie, cookie->parent, cookie->flags, - atomic_read(&cookie->n_children), - atomic_read(&cookie->n_active)); - pr_err("%c-cookie d=%p n=%p\n", - prefix, cookie->def, cookie->netfs_data); - - object = READ_ONCE(cookie->backing_objects.first); - if (object) - pr_err("%c-cookie o=%p\n", - prefix, hlist_entry(object, struct fscache_object, cookie_link)); - - pr_err("%c-key=[%u] '", prefix, cookie->key_len); - k = (cookie->key_len <= sizeof(cookie->inline_key)) ? - cookie->inline_key : cookie->key; - for (loop = 0; loop < cookie->key_len; loop++) - pr_cont("%02x", k[loop]); - pr_cont("'\n"); -} - void fscache_free_cookie(struct fscache_cookie *cookie) { if (cookie) { @@ -284,10 +258,8 @@ struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *candidate) if (test_and_set_bit(FSCACHE_COOKIE_ACQUIRED, &cursor->flags)) { trace_fscache_cookie(cursor, fscache_cookie_collision, atomic_read(&cursor->usage)); - fscache_print_cookie(cursor, 'O'); - fscache_print_cookie(candidate, 'N'); hlist_bl_unlock(h); - pr_err("Duplicate cookie detected\n"); + pr_err_ratelimited("Duplicate cookie detected\n"); return NULL; } -- 2.46.1