From: Rock Li <[email protected]>
We met a crash issue as below:
...
#7 [ff61b991f6f63d10] page_fault at ffffffffab80111e
[exception RIP: iscsi_iser_cleanup_task+13]
RIP: ffffffffc046c04d RSP: ff61b991f6f63dc0 RFLAGS: 00010246
RAX: 0000000000000000 RBX: ff4bd0aalf7a5610 RCX: ff61b991f6f63dc8
RDX: ff61b991f6f63d68 RSI: ff61b991f6f63d58 RDI: ff4bd0aalf6cdc00
RBP: 0000000000000005 R8: 0000000000000073 R9: 0000000000000005
R10: 0000000000000000 R11: 00000ccde3e0f5c0 R12: ff4bd08c0e0631f8
R13: ff4bd0a95ffd3c78 R14: ff4bd0a95ffd3c78 R15: ff4bd0aalf6cdc00
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#8 [ff616991f6f63dc0] __iscsi_put_task at ffffffffc0bd3652 [libiscsi]
#9 [ff61b991f6f63e00] iscsi_put_task at ffffffffc0bd36e9 [libiscsi]
...
After analysing the vmcore, we find that the iser connection was already
stopped before abort handler running. The iser_conn is already unbindded
and released. So we add iser connection validation check inside cleanup
task to fix this corner case.
Signed-off-by: Rock Li <[email protected]>
---
drivers/infiniband/ulp/iser/iscsi_iser.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index bb9aaff92ca3..35dfbf41fc40 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -366,7 +366,12 @@ static void iscsi_iser_cleanup_task(struct iscsi_task *task)
struct iscsi_iser_task *iser_task = task->dd_data;
struct iser_tx_desc *tx_desc = &iser_task->desc;
struct iser_conn *iser_conn = task->conn->dd_data;
- struct iser_device *device = iser_conn->ib_conn.device;
+ struct iser_device *device;
+
+ /* stop connection might happens before iser cleanup work */
+ if (!iser_conn)
+ return;
+ device = iser_conn->ib_conn.device;
/* DEVICE_REMOVAL event might have already released the device */
if (!device)
--
2.27.0
On Tue, Jul 04, 2023 at 08:51:44AM +0800, lihongweizz wrote:
> From: Rock Li <[email protected]>
>
> We met a crash issue as below:
> ...
> #7 [ff61b991f6f63d10] page_fault at ffffffffab80111e
> [exception RIP: iscsi_iser_cleanup_task+13]
> RIP: ffffffffc046c04d RSP: ff61b991f6f63dc0 RFLAGS: 00010246
> RAX: 0000000000000000 RBX: ff4bd0aalf7a5610 RCX: ff61b991f6f63dc8
> RDX: ff61b991f6f63d68 RSI: ff61b991f6f63d58 RDI: ff4bd0aalf6cdc00
> RBP: 0000000000000005 R8: 0000000000000073 R9: 0000000000000005
> R10: 0000000000000000 R11: 00000ccde3e0f5c0 R12: ff4bd08c0e0631f8
> R13: ff4bd0a95ffd3c78 R14: ff4bd0a95ffd3c78 R15: ff4bd0aalf6cdc00
> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
> #8 [ff616991f6f63dc0] __iscsi_put_task at ffffffffc0bd3652 [libiscsi]
> #9 [ff61b991f6f63e00] iscsi_put_task at ffffffffc0bd36e9 [libiscsi]
> ...
>
> After analysing the vmcore, we find that the iser connection was already
> stopped before abort handler running. The iser_conn is already unbindded
> and released. So we add iser connection validation check inside cleanup
> task to fix this corner case.
>
> Signed-off-by: Rock Li <[email protected]>
> ---
> drivers/infiniband/ulp/iser/iscsi_iser.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
> index bb9aaff92ca3..35dfbf41fc40 100644
> --- a/drivers/infiniband/ulp/iser/iscsi_iser.c
> +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
> @@ -366,7 +366,12 @@ static void iscsi_iser_cleanup_task(struct iscsi_task *task)
> struct iscsi_iser_task *iser_task = task->dd_data;
> struct iser_tx_desc *tx_desc = &iser_task->desc;
> struct iser_conn *iser_conn = task->conn->dd_data;
> - struct iser_device *device = iser_conn->ib_conn.device;
> + struct iser_device *device;
> +
> + /* stop connection might happens before iser cleanup work */
> + if (!iser_conn)
> + return;
And what prevents from iser_conn being not valid here?
For example, in the flow:
1. Start iscsi_iser_cleanup_task
2. Get valid task->conn->dd_data
3. Pass this if (..) check
4. Context switch and release connection
5. iser_conn now points to released memory.
Thanks
> + device = iser_conn->ib_conn.device;
>
> /* DEVICE_REMOVAL event might have already released the device */
> if (!device)
> --
> 2.27.0
>
> > On Tue, Jul 04, 2023 at 08:51:44AM +0800, lihongweizz wrote:
> > From: Rock Li <[email protected]>
> >
> > We met a crash issue as below:
> > ...
> > #7 [ff61b991f6f63d10] page_fault at ffffffffab80111e
> > [exception RIP: iscsi_iser_cleanup_task+13]
> > RIP: ffffffffc046c04d RSP: ff61b991f6f63dc0 RFLAGS: 00010246
> > RAX: 0000000000000000 RBX: ff4bd0aalf7a5610 RCX: ff61b991f6f63dc8
> > RDX: ff61b991f6f63d68 RSI: ff61b991f6f63d58 RDI: ff4bd0aalf6cdc00
> > RBP: 0000000000000005 R8: 0000000000000073 R9:
> 0000000000000005
> > R10: 0000000000000000 R11: 00000ccde3e0f5c0 R12:
> ff4bd08c0e0631f8
> > R13: ff4bd0a95ffd3c78 R14: ff4bd0a95ffd3c78 R15: ff4bd0aalf6cdc00
> > ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
> > #8 [ff616991f6f63dc0] __iscsi_put_task at ffffffffc0bd3652 [libiscsi]
> > #9 [ff61b991f6f63e00] iscsi_put_task at ffffffffc0bd36e9 [libiscsi]
> > ...
> >
> > After analysing the vmcore, we find that the iser connection was
> > already stopped before abort handler running. The iser_conn is already
> > unbindded and released. So we add iser connection validation check
> > inside cleanup task to fix this corner case.
> >
> > Signed-off-by: Rock Li <[email protected]>
> > ---
> > drivers/infiniband/ulp/iser/iscsi_iser.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c
> > b/drivers/infiniband/ulp/iser/iscsi_iser.c
> > index bb9aaff92ca3..35dfbf41fc40 100644
> > --- a/drivers/infiniband/ulp/iser/iscsi_iser.c
> > +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
> > @@ -366,7 +366,12 @@ static void iscsi_iser_cleanup_task(struct
iscsi_task
> *task)
> > struct iscsi_iser_task *iser_task = task->dd_data;
> > struct iser_tx_desc *tx_desc = &iser_task->desc;
> > struct iser_conn *iser_conn = task->conn->dd_data;
> > - struct iser_device *device = iser_conn->ib_conn.device;
> > + struct iser_device *device;
> > +
> > + /* stop connection might happens before iser cleanup work */
> > + if (!iser_conn)
> > + return;
>
> And what prevents from iser_conn being not valid here?
> For example, in the flow:
> 1. Start iscsi_iser_cleanup_task
> 2. Get valid task->conn->dd_data
> 3. Pass this if (..) check
> 4. Context switch and release connection 5. iser_conn now points to
released
> memory.
>
> Thanks
Hi Leon,
Thanks for your reply:) In case iscsi_stop_conn was executed cocurrently or
after iscsi_iser_cleanup_task, above issue would happen.
I've confirmed the values in iscsi_cls_conn and iscsi_conn instances from
vmcore:
iscsi_stop_conn
...
WRITE_ONCE(conn->state, ISCSI_CONN_FAILED); --- confirmed
...
conn->transport->stop_conn => iscsi_iser_conn_stop
iscsi_conn_stop
...
conn->c_stage = ISCSI_CONN_STOPPED; --- confirmed
conn->dd_data = NULL; --- confirmed
The crash scene tells us that iscsi_stop_conn was executed before
iscsi_iser_cleanup_task start, the iser_conn instance was already released.
>
> > + device = iser_conn->ib_conn.device;
> >
> > /* DEVICE_REMOVAL event might have already released the device */
> > if (!device)
> > --
> > 2.27.0
> >
On Wed, Jul 05, 2023 at 09:22:08AM +0000, Rock Li(李宏伟) wrote:
> > > On Tue, Jul 04, 2023 at 08:51:44AM +0800, lihongweizz wrote:
> > > From: Rock Li <[email protected]>
> > >
> > > We met a crash issue as below:
> > > ...
> > > #7 [ff61b991f6f63d10] page_fault at ffffffffab80111e
> > > [exception RIP: iscsi_iser_cleanup_task+13]
> > > RIP: ffffffffc046c04d RSP: ff61b991f6f63dc0 RFLAGS: 00010246
> > > RAX: 0000000000000000 RBX: ff4bd0aalf7a5610 RCX: ff61b991f6f63dc8
> > > RDX: ff61b991f6f63d68 RSI: ff61b991f6f63d58 RDI: ff4bd0aalf6cdc00
> > > RBP: 0000000000000005 R8: 0000000000000073 R9:
> > 0000000000000005
> > > R10: 0000000000000000 R11: 00000ccde3e0f5c0 R12:
> > ff4bd08c0e0631f8
> > > R13: ff4bd0a95ffd3c78 R14: ff4bd0a95ffd3c78 R15: ff4bd0aalf6cdc00
> > > ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
> > > #8 [ff616991f6f63dc0] __iscsi_put_task at ffffffffc0bd3652 [libiscsi]
> > > #9 [ff61b991f6f63e00] iscsi_put_task at ffffffffc0bd36e9 [libiscsi]
> > > ...
> > >
> > > After analysing the vmcore, we find that the iser connection was
> > > already stopped before abort handler running. The iser_conn is already
> > > unbindded and released. So we add iser connection validation check
> > > inside cleanup task to fix this corner case.
> > >
> > > Signed-off-by: Rock Li <[email protected]>
> > > ---
> > > drivers/infiniband/ulp/iser/iscsi_iser.c | 7 ++++++-
> > > 1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c
> > > b/drivers/infiniband/ulp/iser/iscsi_iser.c
> > > index bb9aaff92ca3..35dfbf41fc40 100644
> > > --- a/drivers/infiniband/ulp/iser/iscsi_iser.c
> > > +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
> > > @@ -366,7 +366,12 @@ static void iscsi_iser_cleanup_task(struct
> iscsi_task
> > *task)
> > > struct iscsi_iser_task *iser_task = task->dd_data;
> > > struct iser_tx_desc *tx_desc = &iser_task->desc;
> > > struct iser_conn *iser_conn = task->conn->dd_data;
> > > - struct iser_device *device = iser_conn->ib_conn.device;
> > > + struct iser_device *device;
> > > +
> > > + /* stop connection might happens before iser cleanup work */
> > > + if (!iser_conn)
> > > + return;
> >
> > And what prevents from iser_conn being not valid here?
> > For example, in the flow:
> > 1. Start iscsi_iser_cleanup_task
> > 2. Get valid task->conn->dd_data
> > 3. Pass this if (..) check
> > 4. Context switch and release connection 5. iser_conn now points to
> released
> > memory.
> >
> > Thanks
>
> Hi Leon,
> Thanks for your reply:) In case iscsi_stop_conn was executed cocurrently or
> after iscsi_iser_cleanup_task, above issue would happen.
> I've confirmed the values in iscsi_cls_conn and iscsi_conn instances from
> vmcore:
>
> iscsi_stop_conn
> ...
> WRITE_ONCE(conn->state, ISCSI_CONN_FAILED); --- confirmed
> ...
> conn->transport->stop_conn => iscsi_iser_conn_stop
> iscsi_conn_stop
> ...
> conn->c_stage = ISCSI_CONN_STOPPED; --- confirmed
> conn->dd_data = NULL; --- confirmed
>
> The crash scene tells us that iscsi_stop_conn was executed before
> iscsi_iser_cleanup_task start, the iser_conn instance was already released.
It is by chance, it will be better to provide a fix which is race free.
Thanks
>
> >
> > > + device = iser_conn->ib_conn.device;
> > >
> > > /* DEVICE_REMOVAL event might have already released the device */
> > > if (!device)
> > > --
> > > 2.27.0
> > >