6.6-stable review patch. If anyone has any objections, please let me know.
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From: Namjae Jeon linkinjeon@kernel.org
commit 18b4fac5ef17f77fed9417d22210ceafd6525fc7 upstream.
There is a room in smb_break_all_levII_oplock that can cause racy issues when unlocking in the middle of the loop. This patch use read lock to protect whole loop.
Cc: stable@vger.kernel.org Reported-by: Norbert Szetei norbert@doyensec.com Tested-by: Norbert Szetei norbert@doyensec.com Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/server/oplock.c | 29 +++++++++-------------------- fs/smb/server/oplock.h | 1 - 2 files changed, 9 insertions(+), 21 deletions(-)
--- a/fs/smb/server/oplock.c +++ b/fs/smb/server/oplock.c @@ -129,14 +129,6 @@ static void free_opinfo(struct oplock_in kfree(opinfo); }
-static inline void opinfo_free_rcu(struct rcu_head *rcu_head) -{ - struct oplock_info *opinfo; - - opinfo = container_of(rcu_head, struct oplock_info, rcu_head); - free_opinfo(opinfo); -} - struct oplock_info *opinfo_get(struct ksmbd_file *fp) { struct oplock_info *opinfo; @@ -157,8 +149,8 @@ static struct oplock_info *opinfo_get_li if (list_empty(&ci->m_op_list)) return NULL;
- rcu_read_lock(); - opinfo = list_first_or_null_rcu(&ci->m_op_list, struct oplock_info, + down_read(&ci->m_lock); + opinfo = list_first_entry(&ci->m_op_list, struct oplock_info, op_entry); if (opinfo) { if (opinfo->conn == NULL || @@ -171,8 +163,7 @@ static struct oplock_info *opinfo_get_li } } } - - rcu_read_unlock(); + up_read(&ci->m_lock);
return opinfo; } @@ -185,7 +176,7 @@ void opinfo_put(struct oplock_info *opin if (!atomic_dec_and_test(&opinfo->refcount)) return;
- call_rcu(&opinfo->rcu_head, opinfo_free_rcu); + free_opinfo(opinfo); }
static void opinfo_add(struct oplock_info *opinfo) @@ -193,7 +184,7 @@ static void opinfo_add(struct oplock_inf struct ksmbd_inode *ci = opinfo->o_fp->f_ci;
down_write(&ci->m_lock); - list_add_rcu(&opinfo->op_entry, &ci->m_op_list); + list_add(&opinfo->op_entry, &ci->m_op_list); up_write(&ci->m_lock); }
@@ -207,7 +198,7 @@ static void opinfo_del(struct oplock_inf write_unlock(&lease_list_lock); } down_write(&ci->m_lock); - list_del_rcu(&opinfo->op_entry); + list_del(&opinfo->op_entry); up_write(&ci->m_lock); }
@@ -1347,8 +1338,8 @@ void smb_break_all_levII_oplock(struct k ci = fp->f_ci; op = opinfo_get(fp);
- rcu_read_lock(); - list_for_each_entry_rcu(brk_op, &ci->m_op_list, op_entry) { + down_read(&ci->m_lock); + list_for_each_entry(brk_op, &ci->m_op_list, op_entry) { if (brk_op->conn == NULL) continue;
@@ -1358,7 +1349,6 @@ void smb_break_all_levII_oplock(struct k if (ksmbd_conn_releasing(brk_op->conn)) continue;
- rcu_read_unlock(); if (brk_op->is_lease && (brk_op->o_lease->state & (~(SMB2_LEASE_READ_CACHING_LE | SMB2_LEASE_HANDLE_CACHING_LE)))) { @@ -1388,9 +1378,8 @@ void smb_break_all_levII_oplock(struct k oplock_break(brk_op, SMB2_OPLOCK_LEVEL_NONE, NULL); next: opinfo_put(brk_op); - rcu_read_lock(); } - rcu_read_unlock(); + up_read(&ci->m_lock);
if (op) opinfo_put(op); --- a/fs/smb/server/oplock.h +++ b/fs/smb/server/oplock.h @@ -78,7 +78,6 @@ struct oplock_info { struct list_head lease_entry; wait_queue_head_t oplock_q; /* Other server threads */ wait_queue_head_t oplock_brk; /* oplock breaking wait */ - struct rcu_head rcu_head; };
struct lease_break_info {