05 Jun, 2019
1 commit
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Based on 1 normalized pattern(s):
this file is released under the gplv2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 68 file(s).
Signed-off-by: Thomas Gleixner
Reviewed-by: Armijn Hemel
Reviewed-by: Allison Randal
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190114.292346262@linutronix.de
Signed-off-by: Greg Kroah-Hartman
04 Oct, 2017
1 commit
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printk_ratelimit() invokes ___ratelimit() which may invoke a normal
printk() (pr_warn() in this particular case) to warn about suppressed
output. Given that printk_ratelimit() may be called from anywhere, that
pr_warn() is dangerous - it may end up deadlocking the system. Fix
___ratelimit() by using deferred printk().Sasha reported the following lockdep error:
: Unregister pv shared memory for cpu 8
: select_fallback_rq: 3 callbacks suppressed
: process 8583 (trinity-c78) no longer affine to cpu8
:
: ======================================================
: WARNING: possible circular locking dependency detected
: 4.14.0-rc2-next-20170927+ #252 Not tainted
: ------------------------------------------------------
: migration/8/62 is trying to acquire lock:
: (&port_lock_key){-.-.}, at: serial8250_console_write()
:
: but task is already holding lock:
: (&rq->lock){-.-.}, at: sched_cpu_dying()
:
: which lock already depends on the new lock.
:
:
: the existing dependency chain (in reverse order) is:
:
: -> #3 (&rq->lock){-.-.}:
: __lock_acquire()
: lock_acquire()
: _raw_spin_lock()
: task_fork_fair()
: sched_fork()
: copy_process.part.31()
: _do_fork()
: kernel_thread()
: rest_init()
: start_kernel()
: x86_64_start_reservations()
: x86_64_start_kernel()
: verify_cpu()
:
: -> #2 (&p->pi_lock){-.-.}:
: __lock_acquire()
: lock_acquire()
: _raw_spin_lock_irqsave()
: try_to_wake_up()
: default_wake_function()
: woken_wake_function()
: __wake_up_common()
: __wake_up_common_lock()
: __wake_up()
: tty_wakeup()
: tty_port_default_wakeup()
: tty_port_tty_wakeup()
: uart_write_wakeup()
: serial8250_tx_chars()
: serial8250_handle_irq.part.25()
: serial8250_default_handle_irq()
: serial8250_interrupt()
: __handle_irq_event_percpu()
: handle_irq_event_percpu()
: handle_irq_event()
: handle_level_irq()
: handle_irq()
: do_IRQ()
: ret_from_intr()
: native_safe_halt()
: default_idle()
: arch_cpu_idle()
: default_idle_call()
: do_idle()
: cpu_startup_entry()
: rest_init()
: start_kernel()
: x86_64_start_reservations()
: x86_64_start_kernel()
: verify_cpu()
:
: -> #1 (&tty->write_wait){-.-.}:
: __lock_acquire()
: lock_acquire()
: _raw_spin_lock_irqsave()
: __wake_up_common_lock()
: __wake_up()
: tty_wakeup()
: tty_port_default_wakeup()
: tty_port_tty_wakeup()
: uart_write_wakeup()
: serial8250_tx_chars()
: serial8250_handle_irq.part.25()
: serial8250_default_handle_irq()
: serial8250_interrupt()
: __handle_irq_event_percpu()
: handle_irq_event_percpu()
: handle_irq_event()
: handle_level_irq()
: handle_irq()
: do_IRQ()
: ret_from_intr()
: native_safe_halt()
: default_idle()
: arch_cpu_idle()
: default_idle_call()
: do_idle()
: cpu_startup_entry()
: rest_init()
: start_kernel()
: x86_64_start_reservations()
: x86_64_start_kernel()
: verify_cpu()
:
: -> #0 (&port_lock_key){-.-.}:
: check_prev_add()
: __lock_acquire()
: lock_acquire()
: _raw_spin_lock_irqsave()
: serial8250_console_write()
: univ8250_console_write()
: console_unlock()
: vprintk_emit()
: vprintk_default()
: vprintk_func()
: printk()
: ___ratelimit()
: __printk_ratelimit()
: select_fallback_rq()
: sched_cpu_dying()
: cpuhp_invoke_callback()
: take_cpu_down()
: multi_cpu_stop()
: cpu_stopper_thread()
: smpboot_thread_fn()
: kthread()
: ret_from_fork()
:
: other info that might help us debug this:
:
: Chain exists of:
: &port_lock_key --> &p->pi_lock --> &rq->lock
:
: Possible unsafe locking scenario:
:
: CPU0 CPU1
: ---- ----
: lock(&rq->lock);
: lock(&p->pi_lock);
: lock(&rq->lock);
: lock(&port_lock_key);
:
: *** DEADLOCK ***
:
: 4 locks held by migration/8/62:
: #0: (&p->pi_lock){-.-.}, at: sched_cpu_dying()
: #1: (&rq->lock){-.-.}, at: sched_cpu_dying()
: #2: (printk_ratelimit_state.lock){....}, at: ___ratelimit()
: #3: (console_lock){+.+.}, at: vprintk_emit()
:
: stack backtrace:
: CPU: 8 PID: 62 Comm: migration/8 Not tainted 4.14.0-rc2-next-20170927+ #252
: Call Trace:
: dump_stack()
: print_circular_bug()
: check_prev_add()
: ? add_lock_to_list.isra.26()
: ? check_usage()
: ? kvm_clock_read()
: ? kvm_sched_clock_read()
: ? sched_clock()
: ? check_preemption_disabled()
: __lock_acquire()
: ? __lock_acquire()
: ? add_lock_to_list.isra.26()
: ? debug_check_no_locks_freed()
: ? memcpy()
: lock_acquire()
: ? serial8250_console_write()
: _raw_spin_lock_irqsave()
: ? serial8250_console_write()
: serial8250_console_write()
: ? serial8250_start_tx()
: ? lock_acquire()
: ? memcpy()
: univ8250_console_write()
: console_unlock()
: ? __down_trylock_console_sem()
: vprintk_emit()
: vprintk_default()
: vprintk_func()
: printk()
: ? show_regs_print_info()
: ? lock_acquire()
: ___ratelimit()
: __printk_ratelimit()
: select_fallback_rq()
: sched_cpu_dying()
: ? sched_cpu_starting()
: ? rcutree_dying_cpu()
: ? sched_cpu_starting()
: cpuhp_invoke_callback()
: ? cpu_disable_common()
: take_cpu_down()
: ? trace_hardirqs_off_caller()
: ? cpuhp_invoke_callback()
: multi_cpu_stop()
: ? __this_cpu_preempt_check()
: ? cpu_stop_queue_work()
: cpu_stopper_thread()
: ? cpu_stop_create()
: smpboot_thread_fn()
: ? sort_range()
: ? schedule()
: ? __kthread_parkme()
: kthread()
: ? sort_range()
: ? kthread_create_on_node()
: ret_from_fork()
: process 9121 (trinity-c78) no longer affine to cpu8
: smpboot: CPU 8 is now offlineLink: http://lkml.kernel.org/r/20170928120405.18273-1-sergey.senozhatsky@gmail.com
Fixes: 6b1d174b0c27b ("ratelimit: extend to print suppressed messages on release")
Signed-off-by: Sergey Senozhatsky
Reported-by: Sasha Levin
Reviewed-by: Petr Mladek
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Borislav Petkov
Cc: Steven Rostedt
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
03 Aug, 2016
1 commit
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Extend the ratelimiting facility to print the amount of suppressed lines
when it is being released.This use case is aimed at short-termed, burst-like users for which we
want to output the suppressed lines stats only once, after it has been
disposed of. For an example, see /dev/kmsg usage in a follow-on patch.Also, change the printk() line we issue on release to not use
"callbacks" as it is misleading: we're not suppressing callbacks but
printk() calls.This has been separated from a previous patch by Linus.
Link: http://lkml.kernel.org/r/20160716061745.15795-2-bp@alien8.de
Signed-off-by: Borislav Petkov
Cc: Dave Young
Cc: Franck Bui
Cc: Greg Kroah-Hartman
Cc: Ingo Molnar
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: Uwe Kleine-König
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
22 Jan, 2016
1 commit
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rs->begin in ratelimit is set in two cases.
1) when rs->begin was not initialized
2) when rs->interval was passedFor case #2, current ratelimit sets the begin to 0. This incurrs
improper suppression. The begin value will be set in the next ratelimit
call by 1). Then the time interval check will be always false, and
rs->printed will not be initialized. Although enough time passed,
ratelimit may return 0 if rs->printed is not less than rs->burst. To
reset interval properly, begin should be jiffies rather than 0.For an example code below:
static DEFINE_RATELIMIT_STATE(mylimit, 1, 1);
for (i = 1; i
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Mar, 2012
1 commit
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For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include. Fix up any implicit
include dependencies that were being masked by module.h along
the way.Signed-off-by: Paul Gortmaker
13 Sep, 2011
1 commit
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The logbuf_lock lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.Signed-off-by: Thomas Gleixner
[ merged and fixed it ]
Signed-off-by: Ingo Molnar
07 Apr, 2010
2 commits
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The log of commit edaac8e3167501cda336231d00611bf59c164346 ("ratelimit:
Fix/allow use in atomic contexts"), indicates that we want to suppress the
callback when the trylock fails.Signed-off-by: Yong Zhang
Cc: Ingo Molnar
Cc: Christian Borntraeger
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
To prevent from wrongly using the return value.
[akpm@linux-foundation.org: fix spello]
Signed-off-by: Yong Zhang
Cc: Ingo Molnar
Cc: Dave Young
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Oct, 2009
1 commit
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Today I got:
[39648.224782] Registered led device: iwl-phy0::TX
[40676.545099] __ratelimit: 246 callbacks suppressed
[40676.545103] abcdef[23675]: segfault at 0 ...as you can see the ratelimit message contains a function prefix.
Since this is always __ratelimit, this wont help much.This patch changes __ratelimit and printk_ratelimit to print the
function name that calls ratelimit.This will pinpoint the responsible function, as long as not several
different places call ratelimit with the same ratelimit state at
the same time. In that case we catch only one random function that
calls ratelimit after the wait period.Signed-off-by: Christian Borntraeger
Cc: Dave Young
Cc: Linus Torvalds
CC: Andrew Morton
LKML-Reference:
Signed-off-by: Ingo Molnar
22 Sep, 2009
3 commits
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Decouple kernel.h from ratelimit.h: the global declaration of
printk's ratelimit_state is not needed, and it leads to messy
circular dependencies due to ratelimit.h's (new) adding of a
spinlock_types.h include.Cc: Peter Zijlstra
Cc: Andrew Morton
Cc: Linus Torvalds
Cc: David S. Miller
LKML-Reference:
Signed-off-by: Ingo Molnar -
I'd like to use printk_ratelimit() in NMI context, but it's not
robust right now due to spinlock usage in lib/ratelimit.c. If an
NMI is unlucky enough to hit just that spot we might lock up trying
to take the spinlock again.Fix that by using a trylock variant. If we contend on that lock we
can genuinely skip the message because the state is just being
accessed by another CPU (or by this CPU).( We could use atomics for the suppressed messages field, but
i doubt it matters in practice and it makes the code heavier. )Cc: Peter Zijlstra
Cc: Andrew Morton
Cc: Linus Torvalds
Cc: David S. Miller
LKML-Reference:
Signed-off-by: Ingo Molnar -
I'd like to use printk_ratelimit() in atomic context, but that's
not possible right now due to the spinlock usage this commit
introduced more than a year ago:717115e: printk ratelimiting rewrite
As a first step push the lock into the ratelimit state structure.
This allows us to deal with locking failures to be considered as an
event related to that state being too busy.Also clean up the code a bit (without changing functionality):
- tidy up the definitions
- clean up the code flow
This also shrinks the code a tiny bit:
text data bss dec hex filename
264 0 4 268 10c ratelimit.o.before
255 0 0 255 ff ratelimit.o.after( Whole-kernel data size got a bit larger, because we have
two ratelimit-state data structures right now. )Cc: Peter Zijlstra
Cc: Andrew Morton
Cc: Linus Torvalds
Cc: David S. Miller
LKML-Reference:
Signed-off-by: Ingo Molnar
29 Jul, 2008
1 commit
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Signed-off-by: Alexey Dobriyan
Cc: Dave Young
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
26 Jul, 2008
1 commit
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All ratelimit user use same jiffies and burst params, so some messages
(callbacks) will be lost.For example:
a call printk_ratelimit(5 * HZ, 1)
b call printk_ratelimit(5 * HZ, 1) before the 5*HZ timeout of a, then b will
will be supressed.- rewrite __ratelimit, and use a ratelimit_state as parameter. Thanks for
hints from andrew.- Add WARN_ON_RATELIMIT, update rcupreempt.h
- remove __printk_ratelimit
- use __ratelimit in net_ratelimit
Signed-off-by: Dave Young
Cc: "David S. Miller"
Cc: "Paul E. McKenney"
Cc: Dave Young
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Apr, 2008
1 commit
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Due to the rcupreempt.h WARN_ON trigged, I got 2G syslog file. For some
serious complaining of kernel, we need repeat the warnings, so here I isolate
the ratelimit part of printk.c to a standalone file.Signed-off-by: Dave Young
Acked-by: Paul E. McKenney
Tested-by: Paul E. McKenney
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds