Re: [PATCH rdma-rc] RDMA/cm: Fix IRQ restore in ib_send_cm_sidr_rep

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Mar 01, 2021 at 10:18:44AM +0200, Leon Romanovsky wrote:
> From: Saeed Mahameed <saeedm@nvidia.com>
> 
> ib_send_cm_sidr_rep() {
> 	spin_lock_irqsave()
>         cm_send_sidr_rep_locked() {
>                 ...
>         	spin_lock_irq()
>                 ....
>                 spin_unlock_irq() <--- this will enable interrupts
>         }
>         spin_unlock_irqrestore()
> }
> 
> spin_unlock_irqrestore() expects interrupts to be disabled
> but the internal spin_unlock_irq() will always enable hard interrupts.
> 
> Fix this by replacing the internal spin_{lock,unlock}_irq() with
> irqsave/restore variants.
> 
> It fixes the following kernel trace:
> 
>  ------------[ cut here ]------------
>  raw_local_irq_restore() called with IRQs enabled
>  WARNING: CPU: 2 PID: 20001 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x1d/0x20
> 
>  Call Trace:
>   _raw_spin_unlock_irqrestore+0x4e/0x50
>   ib_send_cm_sidr_rep+0x3a/0x50 [ib_cm]
>   cma_send_sidr_rep+0xa1/0x160 [rdma_cm]
>   rdma_accept+0x25e/0x350 [rdma_cm]
>   ucma_accept+0x132/0x1cc [rdma_ucm]
>   ucma_write+0xbf/0x140 [rdma_ucm]
>   vfs_write+0xc1/0x340
>   ksys_write+0xb3/0xe0
>   do_syscall_64+0x2d/0x40
>   entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> Fixes: 87c4c774cbef ("RDMA/cm: Protect access to remote_sidr_table")
> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/infiniband/core/cm.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)

Applied to for-rc, thanks

Jason