From: Rohith Surabattula rohiths@microsoft.com
commit de9ac0a6e9efdffc8cde18781f48fb56ca4157b7 upstream.
cifs_reconnect needs to be called only from demultiplex thread. skip cifs_reconnect in offload thread. So, cifs_reconnect will be called by demultiplex thread in subsequent request.
These patches address a problem found during decryption offload: CIFS: VFS: trying to dequeue a deleted mid that can cause a refcount use after free:
[ 1271.389453] Workqueue: smb3decryptd smb2_decrypt_offload [cifs] [ 1271.389456] RIP: 0010:refcount_warn_saturate+0xae/0xf0 [ 1271.389457] Code: fa 1d 6a 01 01 e8 c7 44 b1 ff 0f 0b 5d c3 80 3d e7 1d 6a 01 00 75 91 48 c7 c7 d8 be 1d a2 c6 05 d7 1d 6a 01 01 e8 a7 44 b1 ff <0f> 0b 5d c3 80 3d c5 1d 6a 01 00 0f 85 6d ff ff ff 48 c7 c7 30 bf [ 1271.389458] RSP: 0018:ffffa4cdc1f87e30 EFLAGS: 00010286 [ 1271.389458] RAX: 0000000000000000 RBX: ffff9974d2809f00 RCX: ffff9974df898cc8 [ 1271.389459] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff9974df898cc0 [ 1271.389460] RBP: ffffa4cdc1f87e30 R08: 0000000000000004 R09: 00000000000002c0 [ 1271.389460] R10: 0000000000000000 R11: 0000000000000001 R12: ffff9974b7fdb5c0 [ 1271.389461] R13: ffff9974d2809f00 R14: ffff9974ccea0a80 R15: ffff99748e60db80 [ 1271.389462] FS: 0000000000000000(0000) GS:ffff9974df880000(0000) knlGS:0000000000000000 [ 1271.389462] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1271.389463] CR2: 000055c60f344fe4 CR3: 0000001031a3c002 CR4: 00000000003706e0 [ 1271.389465] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1271.389465] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1271.389466] Call Trace: [ 1271.389483] cifs_mid_q_entry_release+0xce/0x110 [cifs] [ 1271.389499] smb2_decrypt_offload+0xa9/0x1c0 [cifs] [ 1271.389501] process_one_work+0x1e8/0x3b0 [ 1271.389503] worker_thread+0x50/0x370 [ 1271.389504] kthread+0x12f/0x150 [ 1271.389506] ? process_one_work+0x3b0/0x3b0 [ 1271.389507] ? __kthread_bind_mask+0x70/0x70 [ 1271.389509] ret_from_fork+0x22/0x30
Signed-off-by: Rohith Surabattula rohiths@microsoft.com Reviewed-by: Pavel Shilovsky pshilov@microsoft.com CC: Stable stable@vger.kernel.org #5.4+ Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/cifs/smb2ops.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
--- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -3979,7 +3979,8 @@ init_read_bvec(struct page **pages, unsi static int handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid, char *buf, unsigned int buf_len, struct page **pages, - unsigned int npages, unsigned int page_data_size) + unsigned int npages, unsigned int page_data_size, + bool is_offloaded) { unsigned int data_offset; unsigned int data_len; @@ -4001,7 +4002,8 @@ handle_read_data(struct TCP_Server_Info
if (server->ops->is_session_expired && server->ops->is_session_expired(buf)) { - cifs_reconnect(server); + if (!is_offloaded) + cifs_reconnect(server); wake_up(&server->response_q); return -1; } @@ -4142,7 +4144,8 @@ static void smb2_decrypt_offload(struct mid->decrypted = true; rc = handle_read_data(dw->server, mid, dw->buf, dw->server->vals->read_rsp_size, - dw->ppages, dw->npages, dw->len); + dw->ppages, dw->npages, dw->len, + true); mid->callback(mid); cifs_mid_q_entry_release(mid); } @@ -4246,7 +4249,7 @@ non_offloaded_decrypt: (*mid)->decrypted = true; rc = handle_read_data(server, *mid, buf, server->vals->read_rsp_size, - pages, npages, len); + pages, npages, len, false); }
free_pages: @@ -4391,7 +4394,7 @@ smb3_handle_read_data(struct TCP_Server_ char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
return handle_read_data(server, mid, buf, server->pdu_size, - NULL, 0, 0); + NULL, 0, 0, false); }
static int