Messages in this thread Patch in this message | | | Date | Fri, 18 Jul 2014 03:21:26 -0700 | From | tip-bot for Masami Hiramatsu <> | Subject | [tip:perf/urgent] kprobes: Fix "Failed to find blacklist" probing errors on ia64 and ppc64 |
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Commit-ID: d81b4253b0f0f1e7b7e03b0cd0f80cab18bc4d7b Gitweb: http://git.kernel.org/tip/d81b4253b0f0f1e7b7e03b0cd0f80cab18bc4d7b Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> AuthorDate: Thu, 17 Jul 2014 11:44:11 +0000 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Fri, 18 Jul 2014 06:23:40 +0200
kprobes: Fix "Failed to find blacklist" probing errors on ia64 and ppc64
On ia64 and ppc64, function pointers do not point to the entry address of the function, but to the address of a function descriptor (which contains the entry address and misc data).
Since the kprobes code passes the function pointer stored by NOKPROBE_SYMBOL() to kallsyms_lookup_size_offset() for initalizing its blacklist, it fails and reports many errors, such as:
Failed to find blacklist 0001013168300000 Failed to find blacklist 0001013000f0a000 [...]
To fix this bug, use arch_deref_entry_point() to get the function entry address for kallsyms_lookup_size_offset() instead of the raw function pointer.
Suzuki also pointed out that blacklist entries should also be updated as well.
Reported-by: Tony Luck <tony.luck@gmail.com> Fixed-by: Suzuki K. Poulose <suzuki@in.ibm.com> Tested-by: Tony Luck <tony.luck@intel.com> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (for powerpc) Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: sparse@chrisli.org Cc: Paul Mackerras <paulus@samba.org> Cc: akataria@vmware.com Cc: anil.s.keshavamurthy@intel.com Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Chris Wright <chrisw@sous-sol.org> Cc: yrl.pp-manager.tt@hitachi.com Cc: Kevin Hao <haokexin@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: rdunlap@infradead.org Cc: dl9pf@gmx.de Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: David S. Miller <davem@davemloft.net> Cc: linux-ia64@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20140717114411.13401.2632.stgit@kbuild-fedora.novalocal Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/kprobes.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3214289..734e9a7 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2037,19 +2037,23 @@ static int __init populate_kprobe_blacklist(unsigned long *start, { unsigned long *iter; struct kprobe_blacklist_entry *ent; - unsigned long offset = 0, size = 0; + unsigned long entry, offset = 0, size = 0; for (iter = start; iter < end; iter++) { - if (!kallsyms_lookup_size_offset(*iter, &size, &offset)) { - pr_err("Failed to find blacklist %p\n", (void *)*iter); + entry = arch_deref_entry_point((void *)*iter); + + if (!kernel_text_address(entry) || + !kallsyms_lookup_size_offset(entry, &size, &offset)) { + pr_err("Failed to find blacklist at %p\n", + (void *)entry); continue; } ent = kmalloc(sizeof(*ent), GFP_KERNEL); if (!ent) return -ENOMEM; - ent->start_addr = *iter; - ent->end_addr = *iter + size; + ent->start_addr = entry; + ent->end_addr = entry + size; INIT_LIST_HEAD(&ent->list); list_add_tail(&ent->list, &kprobe_blacklist); }
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