пт, 15 нояб. 2019 г. в 10:07, Pavel Shilovsky <piastryyy@xxxxxxxxx>:
>
> ср, 13 нояб. 2019 г. в 22:17, Ronnie Sahlberg <lsahlber@xxxxxxxxxx>:
> >
> > There is a race where the open() may be interrupted between when we receive the reply
> > but before we have invoked the callback in which case we never end up calling
> > handle_cancelled_mid() and thus leak an open handle on the server.
> >
> > Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> > ---
> > fs/cifs/connect.c | 1 -
> > fs/cifs/transport.c | 2 +-
> > 2 files changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> > index ccaa8bad336f..802604a7e692 100644
> > --- a/fs/cifs/connect.c
> > +++ b/fs/cifs/connect.c
> > @@ -1223,7 +1223,6 @@ cifs_demultiplex_thread(void *p)
> > if (mids[i] != NULL) {
> > mids[i]->resp_buf_size = server->pdu_size;
> > if ((mids[i]->mid_flags & MID_WAIT_CANCELLED) &&
> > - mids[i]->mid_state == MID_RESPONSE_RECEIVED &&
> > server->ops->handle_cancelled_mid)
> > server->ops->handle_cancelled_mid(
> > mids[i]->resp_buf,
> > diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> > index ca3de62688d6..0f219f7653f3 100644
> > --- a/fs/cifs/transport.c
> > +++ b/fs/cifs/transport.c
> > @@ -1119,7 +1119,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
> > midQ[i]->mid, le16_to_cpu(midQ[i]->command));
> > send_cancel(server, &rqst[i], midQ[i]);
> > spin_lock(&GlobalMid_Lock);
> > - if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
> > + if (is_interrupt_error(rc)) {
> > midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
> > midQ[i]->callback = cifs_cancelled_callback;
> > cancelled_mid[i] = true;
> > --
> > 2.13.6
> >
>
> It doesn't seem that RC may be anything other than -ERESTARTSYS but
> is_interrupt_error() should work.
>
> Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
>
> --
> Best regards,
> Pavel Shilovsky
Tested it out. The following part of this change
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index ca3de62688d6..0f219f7653f3 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -1119,7 +1119,7 @@ compound_send_recv(const unsigned int xid,
struct cifs_ses *ses,
midQ[i]->mid, le16_to_cpu(midQ[i]->command));
send_cancel(server, &rqst[i], midQ[i]);
spin_lock(&GlobalMid_Lock);
- if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
+ if (is_interrupt_error(rc)) {
midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
midQ[i]->callback = cifs_cancelled_callback;
cancelled_mid[i] = true;
is causing NULL-pointer dereference on my system:
[681000.970523] BUG: kernel NULL pointer dereference, address: 000000000000000e
[681000.970526] #PF: supervisor read access in kernel mode
[681000.970527] #PF: error_code(0x0000) - not-present page
[681000.970528] PGD 0 P4D 0
[681000.970531] Oops: 0000 [#1] SMP PTI
[681000.970533] CPU: 3 PID: 15946 Comm: cifsd Tainted: G OE
5.3.7-050307-generic #201910180652
[681000.970534] Hardware name: Microsoft Corporation Virtual
Machine/Virtual Machine, BIOS 090008 12/07/2018
[681000.970554] RIP: 0010:smb2_get_credits+0x1f/0x30 [cifs]
[681000.970556] Code: 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
8b 57 6c 55 48 89 e5 83 fa 04 74 09 31 c0 83 fa 10 74 02 5d c3 48 8b
47 60 5d <0f> b7 40 0e c3 66 90 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44
00 00
[681000.970558] RSP: 0018:ffffa9d680433df0 EFLAGS: 00010246
[681000.970559] RAX: 0000000000000000 RBX: ffff9a0ef1775000 RCX:
0000000000000000
[681000.970560] RDX: 0000000000000004 RSI: 0000000000000000 RDI:
ffff9a0ef15c0780
[681000.970561] RBP: ffffa9d680433e18 R08: 0000000000000218 R09:
00000000001bfc3a
[681000.970562] R10: 00000000000dfe1d R11: ffff9a0ef1b7cae0 R12:
ffff9a0ef15c0780
[681000.970563] R13: ffffa9d680433e80 R14: ffffa9d680433ea8 R15:
0000000000000001
[681000.970565] FS: 0000000000000000(0000) GS:ffff9a0ef7b80000(0000)
knlGS:0000000000000000
[681000.970566] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[681000.970566] CR2: 000000000000000e CR3: 00000000e7e0a001 CR4:
00000000003606e0
[681000.970569] Call Trace:
[681000.970585] ? cifs_compound_callback+0x33/0x80 [cifs]
[681000.970599] cifs_compound_last_callback+0x12/0x20 [cifs]
[681000.970611] cifs_demultiplex_thread+0x6d4/0xc40 [cifs]
[681000.970615] kthread+0x104/0x140
[681000.970627] ? cifs_handle_standard+0x190/0x190 [cifs]
[681000.970629] ? kthread_park+0x80/0x80
[681000.970631] ret_from_fork+0x35/0x40
Still haven't figured out why this is happening. Looking.
--
Best regards,
Pavel Shilovsky
