kernel.git/kernel/rcu/tree_stall.h, branch linux-5.9.y

rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled

2020-11-24T12:38:59Z

[ Upstream commit c583bcb8f5edd48c1798798e341f78afb9bf4f6f ] The try_invoke_on_locked_down_task() function requires that interrupts be enabled, but it is called with interrupts disabled from rcu_print_task_stall(), resulting in an "IRQs not enabled as expected" diagnostic. This commit therefore updates rcu_print_task_stall() to accumulate a list of the first few tasks while holding the current leaf rcu_node structure's ->lock, then releases that lock and only then uses try_invoke_on_locked_down_task() to attempt to obtain per-task detailed information. Of course, as soon as ->lock is released, the task might exit, so the get_task_struct() function is used to prevent the task structure from going away in the meantime. Link: https://lore.kernel.org/lkml/000000000000903d5805ab908fc4@google.com/ Fixes: 5bef8da66a9c ("rcu: Add per-task state to RCU CPU stall warnings") Reported-by: syzbot+cb3b69ae80afd6535b0e@syzkaller.appspotmail.com Reported-by: syzbot+f04854e1c5c9e913cc27@syzkaller.appspotmail.com Tested-by: Sebastian Andrzej Siewior Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin

Merge branches 'doc.2020.06.29a', 'fixes.2020.06.29a', 'kfree_rcu.2020.06.29a', 'rcu-tasks.2020.06.29a', 'scale.2020.06.29a', 'srcu.2020.06.29a' and 'torture.2020.06.29a' into HEAD

2020-06-29T19:03:15Z

doc.2020.06.29a: Documentation updates. fixes.2020.06.29a: Miscellaneous fixes. kfree_rcu.2020.06.29a: kfree_rcu() updates. rcu-tasks.2020.06.29a: RCU Tasks updates. scale.2020.06.29a: Read-side scalability tests. srcu.2020.06.29a: SRCU updates. torture.2020.06.29a: Torture-test updates.

rcu: Remove initialized but unused rnp from check_slow_task()

2020-06-29T18:58:50Z

This commit removes the variable rnp from check_slow_task(), which is defined, assigned to, but not otherwise used. Reported-by: kbuild test robot Signed-off-by: Paul E. McKenney

rcu: Add callbacks-invoked counters

2020-06-29T18:58:49Z

This commit adds a count of the callbacks invoked to the per-CPU rcu_data structure. This count is printed by the show_rcu_gp_kthreads() that is invoked by rcutorture and the RCU CPU stall-warning code. It is also intended for use by drgn. Signed-off-by: Paul E. McKenney

docs: RCU: Convert stallwarn.txt to ReST

2020-06-29T18:58:11Z

- Add a SPDX header; - Adjust document and section titles; - Fix list markups; - Some whitespace fixes and new line breaks; - Mark literal blocks as such; - Add it to RCU/index.rst. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Paul E. McKenney

Merge tag 'tty-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2020-06-07T16:52:36Z

Pull tty/serial driver updates from Greg KH: "Here is the tty and serial driver updates for 5.8-rc1 Nothing huge at all, just a lot of little serial driver fixes, updates for new devices and features, and other small things. Full details are in the shortlog. All of these have been in linux-next with no issues for a while" * tag 'tty-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (67 commits) tty: serial: qcom_geni_serial: Add 51.2MHz frequency support tty: serial: imx: clear Ageing Timer Interrupt in handler serial: 8250_fintek: Add F81966 Support sc16is7xx: Add flag to activate IrDA mode dt-bindings: sc16is7xx: Add flag to activate IrDA mode serial: 8250: Support rs485 bus termination GPIO serial: 8520_port: Fix function param documentation dt-bindings: serial: Add binding for rs485 bus termination GPIO vt: keyboard: avoid signed integer overflow in k_ascii serial: 8250: Enable 16550A variants by default on non-x86 tty: hvc_console, fix crashes on parallel open/close serial: imx: Initialize lock for non-registered console sc16is7xx: Read the LSR register for basic device presence check sc16is7xx: Allow sharing the IRQ line sc16is7xx: Use threaded IRQ sc16is7xx: Always use falling edge IRQ tty: n_gsm: Fix bogus i++ in gsm_data_kick tty: n_gsm: Remove unnecessary test in gsm_print_packet() serial: stm32: add no_console_suspend support tty: serial: fsl_lpuart: Use __maybe_unused instead of #if CONFIG_PM_SLEEP ...

rcu: constify sysrq_key_op

2020-05-15T12:53:20Z

With earlier commits, the API no longer discards the const-ness of the sysrq_key_op. As such we can add the notation. Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: linux-kernel@vger.kernel.org Cc: "Paul E. McKenney" Cc: Josh Triplett Cc: rcu@vger.kernel.org Reviewed-by: Paul E. McKenney Signed-off-by: Emil Velikov Link: https://lore.kernel.org/r/20200513214351.2138580-11-emil.l.velikov@gmail.com Signed-off-by: Greg Kroah-Hartman

Merge branches 'fixes.2020.04.27a', 'kfree_rcu.2020.04.27a', 'rcu-tasks.2020.04.27a', 'stall.2020.04.27a' and 'torture.2020.05.07a' into HEAD

2020-05-07T17:18:32Z

fixes.2020.04.27a: Miscellaneous fixes. kfree_rcu.2020.04.27a: Changes related to kfree_rcu(). rcu-tasks.2020.04.27a: Addition of new RCU-tasks flavors. stall.2020.04.27a: RCU CPU stall-warning updates. torture.2020.05.07a: Torture-test updates.

rcu: Remove self-stack-trace when all quiescent states seen

2020-04-27T18:04:37Z

When all quiescent states have been seen, it is normally the grace-period kthread that is in trouble. Although the existing stack trace from the current CPU might possibly provide useful information, experience indicates that there is too much noise for this to be worthwhile. This commit therefore removes this stack trace from the output. Signed-off-by: Paul E. McKenney

rcu: When GP kthread is starved, tag idle threads as false positives

2020-04-27T18:04:37Z

If the grace-period kthread is starved, idle threads' extended quiescent states are not reported. These idle threads thus wrongly appear to be blocking the current grace period. This commit therefore tags such idle threads as probable false positives when the grace-period kthread is being starved. Signed-off-by: Paul E. McKenney