1. 21 Jan, 2013 1 commit
    • Steven Rostedt's avatar
      ftrace: Be first to run code modification on modules · c1bf08ac
      Steven Rostedt authored
      If some other kernel subsystem has a module notifier, and adds a kprobe
      to a ftrace mcount point (now that kprobes work on ftrace points),
      when the ftrace notifier runs it will fail and disable ftrace, as well
      as kprobes that are attached to ftrace points.
      
      Here's the error:
      
       WARNING: at kernel/trace/ftrace.c:1618 ftrace_bug+0x239/0x280()
       Hardware name: Bochs
       Modules linked in: fat(+) stap_56d28a51b3fe546293ca0700b10bcb29__8059(F) nfsv4 auth_rpcgss nfs dns_resolver fscache xt_nat iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack lockd sunrpc ppdev parport_pc parport microcode virtio_net i2c_piix4 drm_kms_helper ttm drm i2c_core [last unloaded: bid_shared]
       Pid: 8068, comm: modprobe Tainted: GF            3.7.0-0.rc8.git0.1.fc19.x86_64 #1
       Call Trace:
        [<ffffffff8105e70f>] warn_slowpath_common+0x7f/0xc0
        [<ffffffff81134106>] ? __probe_kernel_read+0x46/0x70
        [<ffffffffa0180000>] ? 0xffffffffa017ffff
        [<ffffffffa0180000>] ? 0xffffffffa017ffff
        [<ffffffff8105e76a>] warn_slowpath_null+0x1a/0x20
        [<ffffffff810fd189>] ftrace_bug+0x239/0x280
        [<ffffffff810fd626>] ftrace_process_locs+0x376/0x520
        [<ffffffff810fefb7>] ftrace_module_notify+0x47/0x50
        [<ffffffff8163912d>] notifier_call_chain+0x4d/0x70
        [<ffffffff810882f8>] __blocking_notifier_call_chain+0x58/0x80
        [<ffffffff81088336>] blocking_notifier_call_chain+0x16/0x20
        [<ffffffff810c2a23>] sys_init_module+0x73/0x220
        [<ffffffff8163d719>] system_call_fastpath+0x16/0x1b
       ---[ end trace 9ef46351e53bbf80 ]---
       ftrace failed to modify [<ffffffffa0180000>] init_once+0x0/0x20 [fat]
        actual: cc:bb:d2:4b:e1
      
      A kprobe was added to the init_once() function in the fat module on load.
      But this happened before ftrace could have touched the code. As ftrace
      didn't run yet, the kprobe system had no idea it was a ftrace point and
      simply added a breakpoint to the code (0xcc in the cc:bb:d2:4b:e1).
      
      Then when ftrace went to modify the location from a call to mcount/fentry
      into a nop, it didn't see a call op, but instead it saw the breakpoint op
      and not knowing what to do with it, ftrace shut itself down.
      
      The solution is to simply give the ftrace module notifier the max priority.
      This should have been done regardless, as the core code ftrace modification
      also happens very early on in boot up. This makes the module modification
      closer to core modification.
      
      Link: http://lkml.kernel.org/r/20130107140333.593683061@goodmis.org
      
      Cc: stable@vger.kernel.org
      Acked-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Reported-by: default avatarFrank Ch. Eigler <fche@redhat.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      c1bf08ac
  2. 18 Jan, 2013 1 commit
  3. 17 Jan, 2013 2 commits
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux · 72ffaa48
      Linus Torvalds authored
      Pull more s390 patches from Martin Schwidefsky:
       "A couple of bug fixes: one of the transparent huge page primitives is
        broken, the sched_clock function overflows after 417 days, the XFS
        module has grown too large for -fpic and the new pci code has broken
        normal channel subsystem notifications."
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
        s390/chsc: fix SEI usage
        s390/time: fix sched_clock() overflow
        s390: use -fPIC for module compile
        s390/mm: fix pmd_pfn() for thp
      72ffaa48
    • Linus Torvalds's avatar
      Merge tag 'for-linus-v3.8-rc4' of git://oss.sgi.com/xfs/xfs · dfdebc24
      Linus Torvalds authored
      Pull xfs bugfixes from Ben Myers:
      
       - fix(es) for compound buffers
      
       - fix for dquot soft timer asserts due to overflow of d_blk_softlimit
      
       - fix for regression in dir v2 code introduced in commit 20f7e9f3
         ("xfs: factor dir2 block read operations")
      
      * tag 'for-linus-v3.8-rc4' of git://oss.sgi.com/xfs/xfs:
        xfs: recalculate leaf entry pointer after compacting a dir2 block
        xfs: remove int casts from debug dquot soft limit timer asserts
        xfs: fix the multi-segment log buffer format
        xfs: fix segment in xfs_buf_item_format_segment
        xfs: rename bli_format to avoid confusion with bli_formats
        xfs: use b_maps[] for discontiguous buffers
      dfdebc24
  4. 16 Jan, 2013 24 commits
  5. 15 Jan, 2013 11 commits
  6. 14 Jan, 2013 1 commit