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  1. 18 11月, 2006 4 次提交
    • L
      x86: be more careful when walking back the frame pointer chain · 808dbbb6
      由 Linus Torvalds 提交于 
      When showing the stack backtrace, make sure that we never accept not
only an unchanging frame pointer, but also a frame pointer that moves
back down the stack frame.  It must always grow up (toward older stack
frames).

I doubt this has triggered, but a subtly corrupt stack with extremely
unlucky contents could cause us to loop forever on a bogus endless frame
pointer chain.

This review was triggered by much worse problems happening in some of
the other stack unwinding code.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      808dbbb6
    • I
      [PATCH] lockdep: fix static keys in module-allocated percpu areas · 1ff56830
      由 Ingo Molnar 提交于 
      lockdep got confused by certain locks in modules:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.

 Call Trace:
  [<ffffffff8026f40d>] dump_trace+0xaa/0x3f2
  [<ffffffff8026f78f>] show_trace+0x3a/0x60
  [<ffffffff8026f9d1>] dump_stack+0x15/0x17
  [<ffffffff802abfe8>] __lock_acquire+0x724/0x9bb
  [<ffffffff802ac52b>] lock_acquire+0x4d/0x67
  [<ffffffff80267139>] rt_spin_lock+0x3d/0x41
  [<ffffffff8839ed3f>] :ip_conntrack:__ip_ct_refresh_acct+0x131/0x174
  [<ffffffff883a1334>] :ip_conntrack:udp_packet+0xbf/0xcf
  [<ffffffff8839f9af>] :ip_conntrack:ip_conntrack_in+0x394/0x4a7
  [<ffffffff8023551f>] nf_iterate+0x41/0x7f
  [<ffffffff8025946a>] nf_hook_slow+0x64/0xd5
  [<ffffffff802369a2>] ip_rcv+0x24e/0x506
  [...]

Steven Rostedt found the bug: static_obj() check did not take
PERCPU_ENOUGH_ROOM into account, so in-module DEFINE_PER_CPU-area locks
were triggering this message.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      1ff56830
    • I
      [PATCH] i386/x86_64: ACPI cpu_idle_wait() fix · dc1829a4
      由 Ingo Molnar 提交于 
      The scheduler on Andreas Friedrich's hyperthreading system stopped
working properly: the scheduler would never move tasks to another CPU!
The lask known working kernel was 2.6.8.

After a couple of attempts to corner the bug, the following smoking gun
was found:

  BIOS reported wrong ACPI idfor the processor
  CPU#1: set_cpus_allowed(), swapper:1, 3 -> 2
   [<c0103bbe>] show_trace_log_lvl+0x34/0x4a
   [<c0103ceb>] show_trace+0x2c/0x2e
   [<c01045f8>] dump_stack+0x2b/0x2d
   [<c0116a77>] set_cpus_allowed+0x52/0xec
   [<c0101d86>] cpu_idle_wait+0x2e/0x100
   [<c0259c57>] acpi_processor_power_exit+0x45/0x58
   [<c0259752>] acpi_processor_remove+0x46/0xea
   [<c025c6fb>] acpi_start_single_object+0x47/0x54
   [<c025cee5>] acpi_bus_register_driver+0xa4/0xd3
   [<c04ab2d7>] acpi_processor_init+0x57/0x77
   [<c01004d7>] init+0x146/0x2fd
   [<c0103a87>] kernel_thread_helper+0x7/0x10

a quick look at cpu_idle_wait() shows how broken that code is
on i386: it changes the init task's affinity map but never
restores it ...

and because all userspace tasks get forked by init, they all
inherited that single-CPU affinity mask. x86_64 cloned this
bug too.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Andreas Friedrich <andreas.friedrich@fujitsu-siemens.com>
Cc: Wolfgang Erig <Wolfgang.Erig@fujitsu-siemens.com>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      dc1829a4
    • I
      [PATCH] x86_64: stack unwinder crash fix · 0796bdb7
      由 Ingo Molnar 提交于 
      the new dwarf2 unwinder crashes while trying to dump the stack:

  Leftover inexact backtrace:

  Unable to handle kernel paging request at ffffffff82800000 RIP:
   [<ffffffff8026cf26>] dump_trace+0x35b/0x3d2
  PGD 203027 PUD 205027 PMD 0
  Oops: 0000 [2] PREEMPT SMP
  CPU 0
  Modules linked in:
  Pid: 30, comm: khelper Not tainted 2.6.19-rc6-rt1 #11
  RIP: 0010:[<ffffffff8026cf26>]  [<ffffffff8026cf26>] dump_trace+0x35b/0x3d2
  RSP: 0000:ffff81003fb9d848  EFLAGS: 00010006
  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffffffff805b3520 RDI: 0000000000000000
  RBP: ffffffff827ffff9 R08: ffffffff80aad000 R09: 0000000000000005
  R10: ffffffff80aae000 R11: ffffffff8037961b R12: ffff81003fb9d858
  R13: 0000000000000000 R14: ffffffff80598460 R15: ffffffff80ab1fc0
  FS:  0000000000000000(0000) GS:ffffffff806c4200(0000) knlGS:0000000000000000
  CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
  CR2: ffffffff82800000 CR3: 0000000000201000 CR4: 00000000000006e0

this crash happened because it did not sanitize the dwarf2 data it
got, and got an unaligned stack pointer - which happily walked past
the process stack (and eventually reached the end of kernel memory
and pagefaulted there) due to this naive iteration condition:

        HANDLE_STACK (((long) stack & (THREAD_SIZE-1)) != 0);

note that i386 is alot more conservative when it comes to trusting
stack pointers:

  static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
  {
         return  p > (void *)tinfo &&
                 p < (void *)tinfo + THREAD_SIZE - 3;
  }

but the x86_64 code did not take this bit of i386 code.

The fix is to align the stack pointer.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      0796bdb7
  3. 17 11月, 2006 36 次提交