pm24.git/block/blk-ioc.c, branch rust-6.12

blk-ioc: fix recursive spin_lock/unlock_irq() in ioc_clear_queue()

2023-06-07T13:51:00Z

Recursive spin_lock/unlock_irq() is not safe, because spin_unlock_irq() will enable irq unconditionally: spin_lock_irq queue_lock -> disable irq spin_lock_irq ioc->lock spin_unlock_irq ioc->lock -> enable irq /* * AA dead lock will be triggered if current context is preempted by irq, * and irq try to hold queue_lock again. */ spin_unlock_irq queue_lock Fix this problem by using spin_lock/unlock() directly for 'ioc->lock'. Fixes: 5a0ac57c48aa ("blk-ioc: protect ioc_destroy_icq() by 'queue_lock'") Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20230606011438.3743440-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe

blk-ioc: protect ioc_destroy_icq() by 'queue_lock'

2023-06-01T15:13:31Z

Currently, icq is tracked by both request_queue(icq->q_node) and task(icq->ioc_node), and ioc_clear_queue() from elevator exit is not safe because it can access the list without protection: ioc_clear_queue ioc_release_fn lock queue_lock list_splice /* move queue list to a local list */ unlock queue_lock /* * lock is released, the local list * can be accessed through task exit. */ lock ioc->lock while (!hlist_empty) icq = hlist_entry lock queue_lock ioc_destroy_icq delete icq->ioc_node while (!list_empty) icq = list_entry() list_del icq->q_node /* * This is not protected by any lock, * list_entry concurrent with list_del * is not safe. */ unlock queue_lock unlock ioc->lock Fix this problem by protecting list 'icq->q_node' by queue_lock from ioc_clear_queue(). Reported-and-tested-by: Pradeep Pragallapati Link: https://lore.kernel.org/lkml/20230517084434.18932-1-quic_pragalla@quicinc.com/ Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20230531073435.2923422-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe

block: fix default IO priority handling again

2022-06-27T12:29:12Z

Commit e70344c05995 ("block: fix default IO priority handling") introduced an inconsistency in get_current_ioprio() that tasks without IO context return IOPRIO_DEFAULT priority while tasks with freshly allocated IO context will return 0 (IOPRIO_CLASS_NONE/0) IO priority. Tasks without IO context used to be rare before 5a9d041ba2f6 ("block: move io_context creation into where it's needed") but after this commit they became common because now only BFQ IO scheduler setups task's IO context. Similar inconsistency is there for get_task_ioprio() so this inconsistency is now exposed to userspace and userspace will see different IO priority for tasks operating on devices with BFQ compared to devices without BFQ. Furthemore the changes done by commit e70344c05995 change the behavior when no IO priority is set for BFQ IO scheduler which is also documented in ioprio_set(2) manpage: "If no I/O scheduler has been set for a thread, then by default the I/O priority will follow the CPU nice value (setpriority(2)). In Linux kernels before version 2.6.24, once an I/O priority had been set using ioprio_set(), there was no way to reset the I/O scheduling behavior to the default. Since Linux 2.6.24, specifying ioprio as 0 can be used to reset to the default I/O scheduling behavior." So make sure we default to IOPRIO_CLASS_NONE as used to be the case before commit e70344c05995. Also cleanup alloc_io_context() to explicitely set this IO priority for the allocated IO context to avoid future surprises. Note that we tweak ioprio_best() to maintain ioprio_get(2) behavior and make this commit easily backportable. CC: stable@vger.kernel.org Fixes: e70344c05995 ("block: fix default IO priority handling") Reviewed-by: Damien Le Moal Tested-by: Damien Le Moal Signed-off-by: Jan Kara Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220623074840.5960-1-jack@suse.cz Signed-off-by: Jens Axboe

block: restore the old set_task_ioprio() behaviour wrt PF_EXITING

2022-03-28T12:34:11Z

PF_EXITING tasks were silently ignored before the below commits. Continue doing so. Otherwise python-psutil tests fail: ERROR: psutil.tests.test_process.TestProcess.test_zombie_process ---------------------------------------------------------------------- Traceback (most recent call last): File "/home/abuild/rpmbuild/BUILD/psutil-5.9.0/build/lib.linux-x86_64-3.9/psutil/_pslinux.py", line 1661, in wrapper return fun(self, *args, **kwargs) File "/home/abuild/rpmbuild/BUILD/psutil-5.9.0/build/lib.linux-x86_64-3.9/psutil/_pslinux.py", line 2133, in ionice_set return cext.proc_ioprio_set(self.pid, ioclass, value) ProcessLookupError: [Errno 3] No such process During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/home/abuild/rpmbuild/BUILD/psutil-5.9.0/psutil/tests/test_process.py", line 1313, in test_zombie_process succeed_or_zombie_p_exc(fun) File "/home/abuild/rpmbuild/BUILD/psutil-5.9.0/psutil/tests/test_process.py", line 1288, in succeed_or_zombie_p_exc return fun() File "/home/abuild/rpmbuild/BUILD/psutil-5.9.0/build/lib.linux-x86_64-3.9/psutil/__init__.py", line 792, in ionice return self._proc.ionice_set(ioclass, value) File "/home/abuild/rpmbuild/BUILD/psutil-5.9.0/build/lib.linux-x86_64-3.9/psutil/_pslinux.py", line 1665, in wrapper raise NoSuchProcess(self.pid, self._name) psutil.NoSuchProcess: process no longer exists (pid=2057) Cc: Christoph Hellwig Cc: Jan Kara Cc: Jens Axboe Fixes: 5fc11eebb4 (block: open code create_task_io_context in set_task_ioprio) Fixes: a957b61254 (block: fix error in handling dead task for ioprio setting) Signed-off-by: Jiri Slaby Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220328085928.7899-1-jslaby@suse.cz Signed-off-by: Jens Axboe

block: drop needless assignment in set_task_ioprio()

2021-12-23T14:10:07Z

Commit 5fc11eebb4a9 ("block: open code create_task_io_context in set_task_ioprio") introduces a needless assignment 'ioc = task->io_context', as the local variable ioc is not further used before returning. Even after the further fix, commit a957b61254a7 ("block: fix error in handling dead task for ioprio setting"), the assignment still remains needless. Drop this needless assignment in set_task_ioprio(). This code smell was identified with 'make clang-analyzer'. Fixes: 5fc11eebb4a9 ("block: open code create_task_io_context in set_task_ioprio") Signed-off-by: Lukas Bulwahn Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211223125300.20691-1-lukas.bulwahn@gmail.com Signed-off-by: Jens Axboe

block: fix error in handling dead task for ioprio setting

2021-12-21T03:32:24Z

Don't combine the task exiting and "already have io_context" case, we need to just abort if the task is marked as dead. Return -ESRCH, which is the documented value for ioprio_set() if the specified task could not be found. Reported-by: Dan Carpenter Reported-by: syzbot+8836466a79f4175961b0@syzkaller.appspotmail.com Fixes: 5fc11eebb4a9 ("block: open code create_task_io_context in set_task_ioprio") Signed-off-by: Jens Axboe

block: only build the icq tracking code when needed

2021-12-16T17:59:02Z

Only bfq needs to code to track icq, so make it conditional. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20211209063131.18537-12-hch@lst.de Signed-off-by: Jens Axboe

block: fold create_task_io_context into ioc_find_get_icq

2021-12-16T17:59:02Z

Fold create_task_io_context into the only remaining caller. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20211209063131.18537-11-hch@lst.de Signed-off-by: Jens Axboe

block: open code create_task_io_context in set_task_ioprio

2021-12-16T17:59:02Z

The flow in set_task_ioprio can be simplified by simply open coding create_task_io_context, which removes a refcount roundtrip on the I/O context. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20211209063131.18537-10-hch@lst.de Signed-off-by: Jens Axboe

block: fold get_task_io_context into set_task_ioprio

2021-12-16T17:59:02Z

Fold get_task_io_context into its only caller, and simplify the code as no reference to the I/O context is required to just set the ioprio field. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20211209063131.18537-9-hch@lst.de Signed-off-by: Jens Axboe