linux-stable.git/kernel, branch v4.14.70 Linux kernel stable tree mm: Fix devm_memremap_pages() collision handling 2018-09-15T07:45:35+00:00 Jan H. Schönherr jschoenh@amazon.de 2018-01-20T00:26:33+00:00 801fc191bb15655f7e694ba611ee02189f323291 commit 77dd66a3c67c93ab401ccc15efff25578be281fd upstream. If devm_memremap_pages() detects a collision while adding entries to the radix-tree, we call pgmap_radix_release(). Unfortunately, the function removes *all* entries for the range -- including the entries that caused the collision in the first place. Modify pgmap_radix_release() to take an additional argument to indicate where to stop, so that only newly added entries are removed from the tree. Cc: <stable@vger.kernel.org> Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()") Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 77dd66a3c67c93ab401ccc15efff25578be281fd upstream.

If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.

Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.

Cc: <stable@vger.kernel.org>
Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched/deadline: Fix switching to -deadline 2018-09-15T07:45:35+00:00 Luca Abeni luca.abeni@santannapisa.it 2017-09-07T10:09:29+00:00 fd8cb2e71cdd8e814cbdadddd0d0e6e3d49eaa2c commit 295d6d5e373607729bcc8182c25afe964655714f upstream. Fix a bug introduced in: 72f9f3fdc928 ("sched/deadline: Remove dl_new from struct sched_dl_entity") After that commit, when switching to -deadline if the scheduling deadline of a task is in the past then switched_to_dl() calls setup_new_entity() to properly initialize the scheduling deadline and runtime. The problem is that the task is enqueued _before_ having its parameters initialized by setup_new_entity(), and this can cause problems. For example, a task with its out-of-date deadline in the past will potentially be enqueued as the highest priority one; however, its adjusted deadline may not be the earliest one. This patch fixes the problem by initializing the task's parameters before enqueuing it. Signed-off-by: luca abeni <luca.abeni@santannapisa.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1504778971-13573-3-git-send-email-luca.abeni@santannapisa.it Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 295d6d5e373607729bcc8182c25afe964655714f upstream.

Fix a bug introduced in:

  72f9f3fdc928 ("sched/deadline: Remove dl_new from struct sched_dl_entity")

After that commit, when switching to -deadline if the scheduling
deadline of a task is in the past then switched_to_dl() calls
setup_new_entity() to properly initialize the scheduling deadline
and runtime.

The problem is that the task is enqueued _before_ having its parameters
initialized by setup_new_entity(), and this can cause problems.
For example, a task with its out-of-date deadline in the past will
potentially be enqueued as the highest priority one; however, its
adjusted deadline may not be the earliest one.

This patch fixes the problem by initializing the task's parameters before
enqueuing it.

Signed-off-by: luca abeni <luca.abeni@santannapisa.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1504778971-13573-3-git-send-email-luca.abeni@santannapisa.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fork: don't copy inconsistent signal handler state to child 2018-09-15T07:45:27+00:00 Jann Horn jannh@google.com 2018-08-22T05:00:58+00:00 f552f8c28d34ffea62dec915c0a63d900464504b [ Upstream commit 06e62a46bbba20aa5286102016a04214bb446141 ] Before this change, if a multithreaded process forks while one of its threads is changing a signal handler using sigaction(), the memcpy() in copy_sighand() can race with the struct assignment in do_sigaction(). It isn't clear whether this can cause corruption of the userspace signal handler pointer, but it definitely can cause inconsistency between different fields of struct sigaction. Take the appropriate spinlock to avoid this. I have tested that this patch prevents inconsistency between sa_sigaction and sa_flags, which is possible before this patch. Link: http://lkml.kernel.org/r/20180702145108.73189-1-jannh@google.com Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Rik van Riel <riel@redhat.com> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Kees Cook <keescook@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 06e62a46bbba20aa5286102016a04214bb446141 ]

Before this change, if a multithreaded process forks while one of its
threads is changing a signal handler using sigaction(), the memcpy() in
copy_sighand() can race with the struct assignment in do_sigaction().  It
isn't clear whether this can cause corruption of the userspace signal
handler pointer, but it definitely can cause inconsistency between
different fields of struct sigaction.

Take the appropriate spinlock to avoid this.

I have tested that this patch prevents inconsistency between sa_sigaction
and sa_flags, which is possible before this patch.

Link: http://lkml.kernel.org/r/20180702145108.73189-1-jannh@google.com
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
userns: move user access out of the mutex 2018-09-09T17:56:00+00:00 Jann Horn jannh@google.com 2018-06-25T16:34:19+00:00 656d6e6f6d235fe3e349a331ec2d8c5105df721e commit 5820f140edef111a9ea2ef414ab2428b8cb805b1 upstream. The old code would hold the userns_state_mutex indefinitely if memdup_user_nul stalled due to e.g. a userfault region. Prevent that by moving the memdup_user_nul in front of the mutex_lock(). Note: This changes the error precedence of invalid buf/count/*ppos vs map already written / capabilities missing. Fixes: 22d917d80e84 ("userns: Rework the user_namespace adding uid/gid...") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Christian Brauner <christian@brauner.io> Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5820f140edef111a9ea2ef414ab2428b8cb805b1 upstream.

The old code would hold the userns_state_mutex indefinitely if
memdup_user_nul stalled due to e.g. a userfault region. Prevent that by
moving the memdup_user_nul in front of the mutex_lock().

Note: This changes the error precedence of invalid buf/count/*ppos vs
map already written / capabilities missing.

Fixes: 22d917d80e84 ("userns: Rework the user_namespace adding uid/gid...")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Christian Brauner <christian@brauner.io>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sys: don't hold uts_sem while accessing userspace memory 2018-09-09T17:56:00+00:00 Jann Horn jannh@google.com 2018-06-25T16:34:10+00:00 b692c405a1ae577b44764351ad80e99e0a08be99 commit 42a0cc3478584d4d63f68f2f5af021ddbea771fa upstream. Holding uts_sem as a writer while accessing userspace memory allows a namespace admin to stall all processes that attempt to take uts_sem. Instead, move data through stack buffers and don't access userspace memory while uts_sem is held. Cc: stable@vger.kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 42a0cc3478584d4d63f68f2f5af021ddbea771fa upstream.

Holding uts_sem as a writer while accessing userspace memory allows a
namespace admin to stall all processes that attempt to take uts_sem.
Instead, move data through stack buffers and don't access userspace memory
while uts_sem is held.

Cc: stable@vger.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / sleep: wakeup: Fix build error caused by missing SRCU support 2018-09-09T17:55:58+00:00 zhangyi (F) yi.zhang@huawei.com 2018-08-14T02:34:42+00:00 015156f5017987d4164630d763937834dd44506e commit 3df6f61fff49632492490fb6e42646b803a9958a upstream. Commit ea0212f40c6 (power: auto select CONFIG_SRCU) made the code in drivers/base/power/wakeup.c use SRCU instead of RCU, but it forgot to select CONFIG_SRCU in Kconfig, which leads to the following build error if CONFIG_SRCU is not selected somewhere else: drivers/built-in.o: In function `wakeup_source_remove': (.text+0x3c6fc): undefined reference to `synchronize_srcu' drivers/built-in.o: In function `pm_print_active_wakeup_sources': (.text+0x3c7a8): undefined reference to `__srcu_read_lock' drivers/built-in.o: In function `pm_print_active_wakeup_sources': (.text+0x3c84c): undefined reference to `__srcu_read_unlock' drivers/built-in.o: In function `device_wakeup_arm_wake_irqs': (.text+0x3d1d8): undefined reference to `__srcu_read_lock' drivers/built-in.o: In function `device_wakeup_arm_wake_irqs': (.text+0x3d228): undefined reference to `__srcu_read_unlock' drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs': (.text+0x3d24c): undefined reference to `__srcu_read_lock' drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs': (.text+0x3d29c): undefined reference to `__srcu_read_unlock' drivers/built-in.o:(.data+0x4158): undefined reference to `process_srcu' Fix this error by selecting CONFIG_SRCU when PM_SLEEP is enabled. Fixes: ea0212f40c6 (power: auto select CONFIG_SRCU) Cc: 4.2+ <stable@vger.kernel.org> # 4.2+ Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> [ rjw: Minor subject/changelog fixups ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3df6f61fff49632492490fb6e42646b803a9958a upstream.

Commit ea0212f40c6 (power: auto select CONFIG_SRCU) made the code in
drivers/base/power/wakeup.c use SRCU instead of RCU, but it forgot to
select CONFIG_SRCU in Kconfig, which leads to the following build
error if CONFIG_SRCU is not selected somewhere else:

drivers/built-in.o: In function `wakeup_source_remove':
(.text+0x3c6fc): undefined reference to `synchronize_srcu'
drivers/built-in.o: In function `pm_print_active_wakeup_sources':
(.text+0x3c7a8): undefined reference to `__srcu_read_lock'
drivers/built-in.o: In function `pm_print_active_wakeup_sources':
(.text+0x3c84c): undefined reference to `__srcu_read_unlock'
drivers/built-in.o: In function `device_wakeup_arm_wake_irqs':
(.text+0x3d1d8): undefined reference to `__srcu_read_lock'
drivers/built-in.o: In function `device_wakeup_arm_wake_irqs':
(.text+0x3d228): undefined reference to `__srcu_read_unlock'
drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs':
(.text+0x3d24c): undefined reference to `__srcu_read_lock'
drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs':
(.text+0x3d29c): undefined reference to `__srcu_read_unlock'
drivers/built-in.o:(.data+0x4158): undefined reference to `process_srcu'

Fix this error by selecting CONFIG_SRCU when PM_SLEEP is enabled.

Fixes: ea0212f40c6 (power: auto select CONFIG_SRCU)
Cc: 4.2+ <stable@vger.kernel.org> # 4.2+
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
[ rjw: Minor subject/changelog fixups ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uprobes: Use synchronize_rcu() not synchronize_sched() 2018-09-09T17:55:58+00:00 Steven Rostedt (VMware) rostedt@goodmis.org 2018-08-09T19:37:59+00:00 4f6789cad6472a09200a60928ef6c56ae457ed38 commit 016f8ffc48cb01d1e7701649c728c5d2e737d295 upstream. While debugging another bug, I was looking at all the synchronize*() functions being used in kernel/trace, and noticed that trace_uprobes was using synchronize_sched(), with a comment to synchronize with {u,ret}_probe_trace_func(). When looking at those functions, the data is protected with "rcu_read_lock()" and not with "rcu_read_lock_sched()". This is using the wrong synchronize_*() function. Link: http://lkml.kernel.org/r/20180809160553.469e1e32@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 70ed91c6ec7f8 ("tracing/uprobes: Support ftrace_event_file base multibuffer") Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 016f8ffc48cb01d1e7701649c728c5d2e737d295 upstream.

While debugging another bug, I was looking at all the synchronize*()
functions being used in kernel/trace, and noticed that trace_uprobes was
using synchronize_sched(), with a comment to synchronize with
{u,ret}_probe_trace_func(). When looking at those functions, the data is
protected with "rcu_read_lock()" and not with "rcu_read_lock_sched()". This
is using the wrong synchronize_*() function.

Link: http://lkml.kernel.org/r/20180809160553.469e1e32@gandalf.local.home

Cc: stable@vger.kernel.org
Fixes: 70ed91c6ec7f8 ("tracing/uprobes: Support ftrace_event_file base multibuffer")
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
livepatch: Validate module/old func name length 2018-09-09T17:55:58+00:00 Kamalesh Babulal kamalesh@linux.vnet.ibm.com 2018-07-20T09:46:42+00:00 a36e2aa90576263341b3179d47cfe733be7a8085 commit 6e9df95b76cad18f7b217bdad7bb8a26d63b8c47 upstream. livepatch module author can pass module name/old function name with more than the defined character limit. With obj->name length greater than MODULE_NAME_LEN, the livepatch module gets loaded but waits forever on the module specified by obj->name to be loaded. It also populates a /sys directory with an untruncated object name. In the case of funcs->old_name length greater then KSYM_NAME_LEN, it would not match against any of the symbol table entries. Instead loop through the symbol table comparing them against a nonexisting function, which can be avoided. The same issues apply, to misspelled/incorrect names. At least gatekeep the modules with over the limit string length, by checking for their length during livepatch module registration. Cc: stable@vger.kernel.org Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6e9df95b76cad18f7b217bdad7bb8a26d63b8c47 upstream.

livepatch module author can pass module name/old function name with more
than the defined character limit. With obj->name length greater than
MODULE_NAME_LEN, the livepatch module gets loaded but waits forever on
the module specified by obj->name to be loaded. It also populates a /sys
directory with an untruncated object name.

In the case of funcs->old_name length greater then KSYM_NAME_LEN, it
would not match against any of the symbol table entries. Instead loop
through the symbol table comparing them against a nonexisting function,
which can be avoided.

The same issues apply, to misspelled/incorrect names. At least gatekeep
the modules with over the limit string length, by checking for their
length during livepatch module registration.

Cc: stable@vger.kernel.org
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
printk/tracing: Do not trace printk_nmi_enter() 2018-09-09T17:55:57+00:00 Steven Rostedt (VMware) rostedt@goodmis.org 2018-09-05T20:29:49+00:00 68a735eb9a16147a85024c47e6176fe4599b91ef commit d1c392c9e2a301f38998a353f467f76414e38725 upstream. I hit the following splat in my tests: ------------[ cut here ]------------ IRQs not enabled as expected WARNING: CPU: 3 PID: 0 at kernel/time/tick-sched.c:982 tick_nohz_idle_enter+0x44/0x8c Modules linked in: ip6t_REJECT nf_reject_ipv6 ip6table_filter ip6_tables ipv6 CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.19.0-rc2-test+ #2 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 EIP: tick_nohz_idle_enter+0x44/0x8c Code: ec 05 00 00 00 75 26 83 b8 c0 05 00 00 00 75 1d 80 3d d0 36 3e c1 00 75 14 68 94 63 12 c1 c6 05 d0 36 3e c1 01 e8 04 ee f8 ff <0f> 0b 58 fa bb a0 e5 66 c1 e8 25 0f 04 00 64 03 1d 28 31 52 c1 8b EAX: 0000001c EBX: f26e7f8c ECX: 00000006 EDX: 00000007 ESI: f26dd1c0 EDI: 00000000 EBP: f26e7f40 ESP: f26e7f38 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010296 CR0: 80050033 CR2: 0813c6b0 CR3: 2f342000 CR4: 001406f0 Call Trace: do_idle+0x33/0x202 cpu_startup_entry+0x61/0x63 start_secondary+0x18e/0x1ed startup_32_smp+0x164/0x168 irq event stamp: 18773830 hardirqs last enabled at (18773829): [<c040150c>] trace_hardirqs_on_thunk+0xc/0x10 hardirqs last disabled at (18773830): [<c040151c>] trace_hardirqs_off_thunk+0xc/0x10 softirqs last enabled at (18773824): [<c0ddaa6f>] __do_softirq+0x25f/0x2bf softirqs last disabled at (18773767): [<c0416bbe>] call_on_stack+0x45/0x4b ---[ end trace b7c64aa79e17954a ]--- After a bit of debugging, I found what was happening. This would trigger when performing "perf" with a high NMI interrupt rate, while enabling and disabling function tracer. Ftrace uses breakpoints to convert the nops at the start of functions to calls to the function trampolines. The breakpoint traps disable interrupts and this makes calls into lockdep via the trace_hardirqs_off_thunk in the entry.S code. What happens is the following: do_idle { [interrupts enabled] <interrupt> [interrupts disabled] TRACE_IRQS_OFF [lockdep says irqs off] [...] TRACE_IRQS_IRET test if pt_regs say return to interrupts enabled [yes] TRACE_IRQS_ON [lockdep says irqs are on] <nmi> nmi_enter() { printk_nmi_enter() [traced by ftrace] [ hit ftrace breakpoint ] <breakpoint exception> TRACE_IRQS_OFF [lockdep says irqs off] [...] TRACE_IRQS_IRET [return from breakpoint] test if pt_regs say interrupts enabled [no] [iret back to interrupt] [iret back to code] tick_nohz_idle_enter() { lockdep_assert_irqs_enabled() [lockdep say no!] Although interrupts are indeed enabled, lockdep thinks it is not, and since we now do asserts via lockdep, it gives a false warning. The issue here is that printk_nmi_enter() is called before lockdep_off(), which disables lockdep (for this reason) in NMIs. By simply not allowing ftrace to see printk_nmi_enter() (via notrace annotation) we keep lockdep from getting confused. Cc: stable@vger.kernel.org Fixes: 42a0bb3f71383 ("printk/nmi: generic solution for safe printk in NMI") Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d1c392c9e2a301f38998a353f467f76414e38725 upstream.

I hit the following splat in my tests:

------------[ cut here ]------------
IRQs not enabled as expected
WARNING: CPU: 3 PID: 0 at kernel/time/tick-sched.c:982 tick_nohz_idle_enter+0x44/0x8c
Modules linked in: ip6t_REJECT nf_reject_ipv6 ip6table_filter ip6_tables ipv6
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.19.0-rc2-test+ #2
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
EIP: tick_nohz_idle_enter+0x44/0x8c
Code: ec 05 00 00 00 75 26 83 b8 c0 05 00 00 00 75 1d 80 3d d0 36 3e c1 00
75 14 68 94 63 12 c1 c6 05 d0 36 3e c1 01 e8 04 ee f8 ff <0f> 0b 58 fa bb a0
e5 66 c1 e8 25 0f 04 00 64 03 1d 28 31 52 c1 8b
EAX: 0000001c EBX: f26e7f8c ECX: 00000006 EDX: 00000007
ESI: f26dd1c0 EDI: 00000000 EBP: f26e7f40 ESP: f26e7f38
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010296
CR0: 80050033 CR2: 0813c6b0 CR3: 2f342000 CR4: 001406f0
Call Trace:
 do_idle+0x33/0x202
 cpu_startup_entry+0x61/0x63
 start_secondary+0x18e/0x1ed
 startup_32_smp+0x164/0x168
irq event stamp: 18773830
hardirqs last  enabled at (18773829): [<c040150c>] trace_hardirqs_on_thunk+0xc/0x10
hardirqs last disabled at (18773830): [<c040151c>] trace_hardirqs_off_thunk+0xc/0x10
softirqs last  enabled at (18773824): [<c0ddaa6f>] __do_softirq+0x25f/0x2bf
softirqs last disabled at (18773767): [<c0416bbe>] call_on_stack+0x45/0x4b
---[ end trace b7c64aa79e17954a ]---

After a bit of debugging, I found what was happening. This would trigger
when performing "perf" with a high NMI interrupt rate, while enabling and
disabling function tracer. Ftrace uses breakpoints to convert the nops at
the start of functions to calls to the function trampolines. The breakpoint
traps disable interrupts and this makes calls into lockdep via the
trace_hardirqs_off_thunk in the entry.S code. What happens is the following:

  do_idle {

    [interrupts enabled]

    <interrupt> [interrupts disabled]
	TRACE_IRQS_OFF [lockdep says irqs off]
	[...]
	TRACE_IRQS_IRET
	    test if pt_regs say return to interrupts enabled [yes]
	    TRACE_IRQS_ON [lockdep says irqs are on]

	    <nmi>
		nmi_enter() {
		    printk_nmi_enter() [traced by ftrace]
		    [ hit ftrace breakpoint ]
		    <breakpoint exception>
			TRACE_IRQS_OFF [lockdep says irqs off]
			[...]
			TRACE_IRQS_IRET [return from breakpoint]
			   test if pt_regs say interrupts enabled [no]
			   [iret back to interrupt]
	   [iret back to code]

    tick_nohz_idle_enter() {

	lockdep_assert_irqs_enabled() [lockdep say no!]

Although interrupts are indeed enabled, lockdep thinks it is not, and since
we now do asserts via lockdep, it gives a false warning. The issue here is
that printk_nmi_enter() is called before lockdep_off(), which disables
lockdep (for this reason) in NMIs. By simply not allowing ftrace to see
printk_nmi_enter() (via notrace annotation) we keep lockdep from getting
confused.

Cc: stable@vger.kernel.org
Fixes: 42a0bb3f71383 ("printk/nmi: generic solution for safe printk in NMI")
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/blktrace: Fix to allow setting same value 2018-09-09T17:55:57+00:00 Steven Rostedt (VMware) rostedt@goodmis.org 2018-08-16T20:08:37+00:00 cbde057aa0e7b2fcca06e7f6ba28b8d76a041ce9 commit 757d9140072054528b13bbe291583d9823cde195 upstream. Masami Hiramatsu reported: Current trace-enable attribute in sysfs returns an error if user writes the same setting value as current one, e.g. # cat /sys/block/sda/trace/enable 0 # echo 0 > /sys/block/sda/trace/enable bash: echo: write error: Invalid argument # echo 1 > /sys/block/sda/trace/enable # echo 1 > /sys/block/sda/trace/enable bash: echo: write error: Device or resource busy But this is not a preferred behavior, it should ignore if new setting is same as current one. This fixes the problem as below. # cat /sys/block/sda/trace/enable 0 # echo 0 > /sys/block/sda/trace/enable # echo 1 > /sys/block/sda/trace/enable # echo 1 > /sys/block/sda/trace/enable Link: http://lkml.kernel.org/r/20180816103802.08678002@gandalf.local.home Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Cc: stable@vger.kernel.org Fixes: cd649b8bb830d ("blktrace: remove sysfs_blk_trace_enable_show/store()") Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 757d9140072054528b13bbe291583d9823cde195 upstream.

Masami Hiramatsu reported:

  Current trace-enable attribute in sysfs returns an error
  if user writes the same setting value as current one,
  e.g.

    # cat /sys/block/sda/trace/enable
    0
    # echo 0 > /sys/block/sda/trace/enable
    bash: echo: write error: Invalid argument
    # echo 1 > /sys/block/sda/trace/enable
    # echo 1 > /sys/block/sda/trace/enable
    bash: echo: write error: Device or resource busy

  But this is not a preferred behavior, it should ignore
  if new setting is same as current one. This fixes the
  problem as below.

    # cat /sys/block/sda/trace/enable
    0
    # echo 0 > /sys/block/sda/trace/enable
    # echo 1 > /sys/block/sda/trace/enable
    # echo 1 > /sys/block/sda/trace/enable

Link: http://lkml.kernel.org/r/20180816103802.08678002@gandalf.local.home

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: cd649b8bb830d ("blktrace: remove sysfs_blk_trace_enable_show/store()")
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>