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1a19755519
There is a long call chain that &fip->ctlr_lock is acquired by isr
fnic_isr_msix_wq_copy() under hard IRQ context. Thus other process context
code acquiring the lock 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.
[ISR]
fnic_isr_msix_wq_copy()
-> fnic_wq_copy_cmpl_handler()
-> fnic_fcpio_cmpl_handler()
-> fnic_fcpio_flogi_reg_cmpl_handler()
-> fnic_flush_tx()
-> fnic_send_frame()
-> fcoe_ctlr_els_send()
-> spin_lock_bh(&fip->ctlr_lock)
[Process Context]
1. fcoe_ctlr_timer_work()
-> fcoe_ctlr_flogi_send()
-> spin_lock_bh(&fip->ctlr_lock)
2. fcoe_ctlr_recv_work()
-> fcoe_ctlr_recv_handler()
-> fcoe_ctlr_recv_els()
-> fcoe_ctlr_announce()
-> spin_lock_bh(&fip->ctlr_lock)
3. fcoe_ctlr_recv_work()
-> fcoe_ctlr_recv_handler()
-> fcoe_ctlr_recv_els()
-> fcoe_ctlr_flogi_retry()
-> spin_lock_bh(&fip->ctlr_lock)
4. -> fcoe_xmit()
-> fcoe_ctlr_els_send()
-> spin_lock_bh(&fip->ctlr_lock)
spin_lock_bh() is not enough since fnic_isr_msix_wq_copy() is a
hardirq.
These flaws were found by an experimental static analysis tool I am
developing for irq-related deadlock.
The patch fix the potential deadlocks by spin_lock_irqsave() to disable
hard irq.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
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| samples | ||
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| .clang-format | ||
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| README | ||
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.