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  1. 24 10月, 2013 1 次提交
  3. 04 10月, 2013 1 次提交
  5. 01 10月, 2013 4 次提交
    • F
      irq: Force hardirq exit's softirq processing on its own stack · ded79754
      由 Frederic Weisbecker 提交于 
      The commit facd8b80
("irq: Sanitize invoke_softirq") converted irq exit
calls of do_softirq() to __do_softirq() on all architectures,
assuming it was only used there for its irq disablement
properties.

But as a side effect, the softirqs processed in the end
of the hardirq are always called on the inline current
stack that is used by irq_exit() instead of the softirq
stack provided by the archs that override do_softirq().

The result is mostly safe if the architecture runs irq_exit()
on a separate irq stack because then softirqs are processed
on that same stack that is near empty at this stage (assuming
hardirq aren't nesting).

Otherwise irq_exit() runs in the task stack and so does the softirq
too. The interrupted call stack can be randomly deep already and
the softirq can dig through it even further. To add insult to the
injury, this softirq can be interrupted by a new hardirq, maximizing
the chances for a stack overrun as reported in powerpc for example:

	do_IRQ: stack overflow: 1920
	CPU: 0 PID: 1602 Comm: qemu-system-ppc Not tainted 3.10.4-300.1.fc19.ppc64p7 #1
	Call Trace:
	[c0000000050a8740] .show_stack+0x130/0x200 (unreliable)
	[c0000000050a8810] .dump_stack+0x28/0x3c
	[c0000000050a8880] .do_IRQ+0x2b8/0x2c0
	[c0000000050a8930] hardware_interrupt_common+0x154/0x180
	--- Exception: 501 at .cp_start_xmit+0x3a4/0x820 [8139cp]
		LR = .cp_start_xmit+0x390/0x820 [8139cp]
	[c0000000050a8d40] .dev_hard_start_xmit+0x394/0x640
	[c0000000050a8e00] .sch_direct_xmit+0x110/0x260
	[c0000000050a8ea0] .dev_queue_xmit+0x260/0x630
	[c0000000050a8f40] .br_dev_queue_push_xmit+0xc4/0x130 [bridge]
	[c0000000050a8fc0] .br_dev_xmit+0x198/0x270 [bridge]
	[c0000000050a9070] .dev_hard_start_xmit+0x394/0x640
	[c0000000050a9130] .dev_queue_xmit+0x428/0x630
	[c0000000050a91d0] .ip_finish_output+0x2a4/0x550
	[c0000000050a9290] .ip_local_out+0x50/0x70
	[c0000000050a9310] .ip_queue_xmit+0x148/0x420
	[c0000000050a93b0] .tcp_transmit_skb+0x4e4/0xaf0
	[c0000000050a94a0] .__tcp_ack_snd_check+0x7c/0xf0
	[c0000000050a9520] .tcp_rcv_established+0x1e8/0x930
	[c0000000050a95f0] .tcp_v4_do_rcv+0x21c/0x570
	[c0000000050a96c0] .tcp_v4_rcv+0x734/0x930
	[c0000000050a97a0] .ip_local_deliver_finish+0x184/0x360
	[c0000000050a9840] .ip_rcv_finish+0x148/0x400
	[c0000000050a98d0] .__netif_receive_skb_core+0x4f8/0xb00
	[c0000000050a99d0] .netif_receive_skb+0x44/0x110
	[c0000000050a9a70] .br_handle_frame_finish+0x2bc/0x3f0 [bridge]
	[c0000000050a9b20] .br_nf_pre_routing_finish+0x2ac/0x420 [bridge]
	[c0000000050a9bd0] .br_nf_pre_routing+0x4dc/0x7d0 [bridge]
	[c0000000050a9c70] .nf_iterate+0x114/0x130
	[c0000000050a9d30] .nf_hook_slow+0xb4/0x1e0
	[c0000000050a9e00] .br_handle_frame+0x290/0x330 [bridge]
	[c0000000050a9ea0] .__netif_receive_skb_core+0x34c/0xb00
	[c0000000050a9fa0] .netif_receive_skb+0x44/0x110
	[c0000000050aa040] .napi_gro_receive+0xe8/0x120
	[c0000000050aa0c0] .cp_rx_poll+0x31c/0x590 [8139cp]
	[c0000000050aa1d0] .net_rx_action+0x1dc/0x310
	[c0000000050aa2b0] .__do_softirq+0x158/0x330
	[c0000000050aa3b0] .irq_exit+0xc8/0x110
	[c0000000050aa430] .do_IRQ+0xdc/0x2c0
	[c0000000050aa4e0] hardware_interrupt_common+0x154/0x180
	 --- Exception: 501 at .bad_range+0x1c/0x110
		 LR = .get_page_from_freelist+0x908/0xbb0
	[c0000000050aa7d0] .list_del+0x18/0x50 (unreliable)
	[c0000000050aa850] .get_page_from_freelist+0x908/0xbb0
	[c0000000050aa9e0] .__alloc_pages_nodemask+0x21c/0xae0
	[c0000000050aaba0] .alloc_pages_vma+0xd0/0x210
	[c0000000050aac60] .handle_pte_fault+0x814/0xb70
	[c0000000050aad50] .__get_user_pages+0x1a4/0x640
	[c0000000050aae60] .get_user_pages_fast+0xec/0x160
	[c0000000050aaf10] .__gfn_to_pfn_memslot+0x3b0/0x430 [kvm]
	[c0000000050aafd0] .kvmppc_gfn_to_pfn+0x64/0x130 [kvm]
	[c0000000050ab070] .kvmppc_mmu_map_page+0x94/0x530 [kvm]
	[c0000000050ab190] .kvmppc_handle_pagefault+0x174/0x610 [kvm]
	[c0000000050ab270] .kvmppc_handle_exit_pr+0x464/0x9b0 [kvm]
	[c0000000050ab320]  kvm_start_lightweight+0x1ec/0x1fc [kvm]
	[c0000000050ab4f0] .kvmppc_vcpu_run_pr+0x168/0x3b0 [kvm]
	[c0000000050ab9c0] .kvmppc_vcpu_run+0xc8/0xf0 [kvm]
	[c0000000050aba50] .kvm_arch_vcpu_ioctl_run+0x5c/0x1a0 [kvm]
	[c0000000050abae0] .kvm_vcpu_ioctl+0x478/0x730 [kvm]
	[c0000000050abc90] .do_vfs_ioctl+0x4ec/0x7c0
	[c0000000050abd80] .SyS_ioctl+0xd4/0xf0
	[c0000000050abe30] syscall_exit+0x0/0x98

Since this is a regression, this patch proposes a minimalistic
and low-risk solution by blindly forcing the hardirq exit processing of
softirqs on the softirq stack. This way we should reduce significantly
the opportunities for task stack overflow dug by softirqs.

Longer term solutions may involve extending the hardirq stack coverage to
irq_exit(), etc...
Reported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: #3.9.. <stable@vger.kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@au1.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@au1.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
      ded79754
    • O
      pidns: fix free_pid() to handle the first fork failure · 314a8ad0
      由 Oleg Nesterov 提交于 
      "case 0" in free_pid() assumes that disable_pid_allocation() should
clear PIDNS_HASH_ADDING before the last pid goes away.

However this doesn't happen if the first fork() fails to create the
child reaper which should call disable_pid_allocation().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Reviewed-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      314a8ad0
    • T
      kernel/kmod.c: check for NULL in call_usermodehelper_exec() · 4c1c7be9
      由 Tetsuo Handa 提交于 
      If /proc/sys/kernel/core_pattern contains only "|", a NULL pointer
dereference happens upon core dump because argv_split("") returns
argv[0] == NULL.

This bug was once fixed by commit 264b83c0 ("usermodehelper: check
subprocess_info->path != NULL") but was by error reintroduced by commit
7f57cfa4 ("usermodehelper: kill the sub_info->path[0] check").

This bug seems to exist since 2.6.19 (the version which core dump to
pipe was added).  Depending on kernel version and config, some side
effect might happen immediately after this oops (e.g.  kernel panic with
2.6.32-358.18.1.el6).
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4c1c7be9
    • R
      PM / hibernate: Fix user space driven resume regression · aab17289
      由 Rafael J. Wysocki 提交于 
      Recent commit 8fd37a4c (PM / hibernate: Create memory bitmaps after
freezing user space) broke the resume part of the user space driven
hibernation (s2disk), because I forgot that the resume utility
loaded the image into memory without freezing user space (it still
freezes tasks after loading the image).  This means that during user
space driven resume we need to create the memory bitmaps at the
"device open" time rather than at the "freeze tasks" time, so make
that happen (that's a special case anyway, so it needs to be treated
in a special way).
Reported-and-tested-by: NRonald <ronald645@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      aab17289
  7. 29 9月, 2013 1 次提交
  9. 27 9月, 2013 1 次提交
  11. 25 9月, 2013 4 次提交
    • C
      kernel/reboot.c: re-enable the function of variable reboot_default · e2f0b88e
      由 Chuansheng Liu 提交于 
      Commit 1b3a5d02 ("reboot: move arch/x86 reboot= handling to generic
kernel") did some cleanup for reboot= command line, but it made the
reboot_default inoperative.

The default value of variable reboot_default should be 1, and if command
line reboot= is not set, system will use the default reboot mode.

[akpm@linux-foundation.org: fix comment layout]
Signed-off-by: NLi Fei <fei.li@intel.com>
Signed-off-by: Nliu chuansheng <chuansheng.liu@intel.com>
Acked-by: NRobin Holt <robinmholt@linux.com>
Cc: <stable@vger.kernel.org>	[3.11.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e2f0b88e
    • K
      audit: fix endless wait in audit_log_start() · 8ac1c8d5
      由 Konstantin Khlebnikov 提交于 
      After commit 82919919 ("kernel/audit.c: avoid negative sleep
durations") audit emitters will block forever if userspace daemon cannot
handle backlog.

After the timeout the waiting loop turns into busy loop and runs until
daemon dies or returns back to work.  This is a minimal patch for that
bug.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Chuck Anderson <chuck.anderson@oracle.com>
Cc: Dan Duval <dan.duval@oracle.com>
Cc: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8ac1c8d5
    • M
      watchdog: update watchdog_thresh properly · 9809b18f
      由 Michal Hocko 提交于 
      watchdog_tresh controls how often nmi perf event counter checks per-cpu
hrtimer_interrupts counter and blows up if the counter hasn't changed
since the last check.  The counter is updated by per-cpu
watchdog_hrtimer hrtimer which is scheduled with 2/5 watchdog_thresh
period which guarantees that hrtimer is scheduled 2 times per the main
period.  Both hrtimer and perf event are started together when the
watchdog is enabled.

So far so good.  But...

But what happens when watchdog_thresh is updated from sysctl handler?

proc_dowatchdog will set a new sampling period and hrtimer callback
(watchdog_timer_fn) will use the new value in the next round.  The
problem, however, is that nobody tells the perf event that the sampling
period has changed so it is ticking with the period configured when it
has been set up.

This might result in an ear ripping dissonance between perf and hrtimer
parts if the watchdog_thresh is increased.  And even worse it might lead
to KABOOM if the watchdog is configured to panic on such a spurious
lockup.

This patch fixes the issue by updating both nmi perf even counter and
hrtimers if the threshold value has changed.

The nmi one is disabled and then reinitialized from scratch.  This has
an unpleasant side effect that the allocation of the new event might
fail theoretically so the hard lockup detector would be disabled for
such cpus.  On the other hand such a memory allocation failure is very
unlikely because the original event is deallocated right before.

It would be much nicer if we just changed perf event period but there
doesn't seem to be any API to do that right now.  It is also unfortunate
that perf_event_alloc uses GFP_KERNEL allocation unconditionally so we
cannot use on_each_cpu() and do the same thing from the per-cpu context.
The update from the current CPU should be safe because
perf_event_disable removes the event atomically before it clears the
per-cpu watchdog_ev so it cannot change anything under running handler
feet.

The hrtimer is simply restarted (thanks to Don Zickus who has pointed
this out) if it is queued because we cannot rely it will fire&adopt to
the new sampling period before a new nmi event triggers (when the
treshold is decreased).

[akpm@linux-foundation.org: the UP version of __smp_call_function_single ended up in the wrong place]
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NDon Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9809b18f
    • M
      watchdog: update watchdog attributes atomically · 359e6fab
      由 Michal Hocko 提交于 
      proc_dowatchdog doesn't synchronize multiple callers which might lead to
confusion when two parallel callers might confuse watchdog_enable_all_cpus
resp watchdog_disable_all_cpus (eg watchdog gets enabled even if
watchdog_thresh was set to 0 already).

This patch adds a local mutex which synchronizes callers to the sysctl
handler.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      359e6fab
  13. 20 9月, 2013 4 次提交
  15. 16 9月, 2013 1 次提交
  17. 13 9月, 2013 7 次提交
  19. 12 9月, 2013 16 次提交