Re: [PATCH] infiniband: core: mad: Fix a sleep-in-atomic-context bug in ib_mad_recv_done()

[Jia-Ju Bai]

On 2018/9/3 4:32, Jason Gunthorpe wrote:

On Sat, Sep 01, 2018 at 08:06:59PM +0800, Jia-Ju Bai wrote:

The driver may sleep with holding a spinlock.

The function call paths (from bottom to top) in Linux-4.16 are:

[FUNC] alloc_mad_private(GFP_KERNEL)
drivers/infiniband/core/mad.c, 2264:
        alloc_mad_private in ib_mad_recv_done
drivers/infiniband/core/cq.c, 45:
        [FUNC_PTR]ib_mad_recv_done in __ib_process_cq
drivers/infiniband/core/cq.c, 77:
        __ib_process_cq in ib_process_cq_direct
drivers/infiniband/ulp/srp/ib_srp.c, 2010:
        ib_process_cq_direct in __srp_get_tx_iu
drivers/infiniband/ulp/srp/ib_srp.c, 2353:
        __srp_get_tx_iu in srp_queuecommand
drivers/infiniband/ulp/srp/ib_srp.c, 2352:
        _raw_spin_lock_irqsave in srp_queuecommand

[FUNC] alloc_mad_private(GFP_KERNEL)
drivers/infiniband/core/mad.c, 2264:
        alloc_mad_private in ib_mad_recv_done
drivers/infiniband/core/cq.c, 45:
        [FUNC_PTR]ib_mad_recv_done in __ib_process_cq
drivers/infiniband/core/cq.c, 77:
        __ib_process_cq in ib_process_cq_direct

This trace doesn't seem right, the CQ used by SRP will never have
ib_mad_recv_done as a function pointer.

Okay, sorry for this false positive.


Best wishes,
Jia-Ju Bai