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Commit 28356a16 authored by Steve French's avatar Steve French
Browse files

[CIFS] Fix oops on failed cifs mount (in kthread_stop) 



If the cifs demultiplex thread wakes up and exits
(zeroing server->tsk) before kthread_stop is called, the
cifs_mount code could pass a null pointer to kthread_stop

Thanks to akpm, Dave Young and Shaggy for suggesting
earlier versions of this patch.

CC: akpm@linux-foundatior.org
Signed-off-by: default avatarDave Young <hidave.darkstar@gmail.com>
Signed-off-by: default avatarDave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent ad9ddd66

fs/cifs/connect.c

+12 −2
Original line number Diff line number Diff line
@@ -2069,7 +2069,14 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb, 
			srvTcp->tcpStatus = CifsExiting;

			spin_unlock(&GlobalMid_Lock);

			if (srvTcp->tsk) {

				struct task_struct *tsk;

				/* If we could verify that kthread_stop would

				   always wake up processes blocked in

				   tcp in recv_mesg then we could remove the

				   send_sig call */

				send_sig(SIGKILL,srvTcp->tsk,1);

				tsk = srvTcp->tsk;

				if(tsk)

					kthread_stop(srvTcp->tsk);

			}

		}
@@ -2085,8 +2092,11 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb, 
					/* if the socketUseCount is now zero */

					if ((temp_rc == -ESHUTDOWN) &&

					   (pSesInfo->server) && (pSesInfo->server->tsk)) {

						struct task_struct *tsk;

						send_sig(SIGKILL,pSesInfo->server->tsk,1);

						kthread_stop(pSesInfo->server->tsk);

						tsk = pSesInfo->server->tsk;

						if(tsk)

							kthread_stop(tsk);

					}

				} else

					cFYI(1, ("No session or bad tcon"));