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b3134b8c1a
When CONFIG_DEBUG_RT_MUTEXES=y, mutex_lock->rt_mutex_try_acquire
would change from rt_mutex_cmpxchg_acquire to
rt_mutex_slowtrylock():
raw_spin_lock_irqsave(&lock->wait_lock, flags);
ret = __rt_mutex_slowtrylock(lock);
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
Because queued_spin_#ops to ticket_#ops is changed one by one by
jump_label, raw_spin_lock/unlock would cause a deadlock during the
changing.
That means in arch/riscv/kernel/jump_label.c:
1.
arch_jump_label_transform_queue() ->
mutex_lock(&text_mutex); +-> raw_spin_lock -> queued_spin_lock
|-> raw_spin_unlock -> queued_spin_unlock
patch_insn_write -> change the raw_spin_lock to ticket_lock
mutex_unlock(&text_mutex);
...
2. /* Dirty the lock value */
arch_jump_label_transform_queue() ->
mutex_lock(&text_mutex); +-> raw_spin_lock -> *ticket_lock*
|-> raw_spin_unlock -> *queued_spin_unlock*
/* BUG: ticket_lock with queued_spin_unlock */
patch_insn_write -> change the raw_spin_unlock to ticket_unlock
mutex_unlock(&text_mutex);
...
3. /* Dead lock */
arch_jump_label_transform_queue() ->
mutex_lock(&text_mutex); +-> raw_spin_lock -> ticket_lock /* deadlock! */
|-> raw_spin_unlock -> ticket_unlock
patch_insn_write -> change other raw_spin_#op -> ticket_#op
mutex_unlock(&text_mutex);
So, the solution is to disable mutex usage of
arch_jump_label_transform_queue() during early_boot_irqs_disabled, just
like we have done for stop_machine.
Reported-by: Conor Dooley <conor@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 reStructuredText 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.