dd64f80587
As &qedi_percpu->p_work_lock is acquired by hard IRQ qedi_msix_handler(),
other acquisitions of the same lock under process context should disable
IRQ, otherwise deadlock could happen if the IRQ preempts the execution
while the lock is held in process context on the same CPU.
qedi_cpu_offline() is one such function which acquires the lock in process
context.
[Deadlock Scenario]
qedi_cpu_offline()
->spin_lock(&p->p_work_lock)
<irq>
->qedi_msix_handler()
->edi_process_completions()
->spin_lock_irqsave(&p->p_work_lock, flags); (deadlock here)
This flaw was found by an experimental static analysis tool I am developing
for IRQ-related deadlocks.
The tentative patch fix the potential deadlock by spin_lock_irqsave()
under process context.
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Link: https://lore.kernel.org/r/20230726125655.4197-1-dg573847474@gmail.com
Acked-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.