Messages in this thread Patch in this message | | | Subject | [PATCH] [GIT PULL] tracing: allow to change permissions for text with dynamic ftrace enabled | From | Steven Rostedt <> | Date | Tue, 27 Oct 2009 13:53:43 -0400 |
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Ingo,
The cause of the ftrace bug you saw in tip/master was caused by a change in tip's x86/mm branch.
Please pull the latest tip/x86/mm tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git tip/x86/mm
Steven Rostedt (1): tracing: allow to change permissions for text with dynamic ftrace enabled
---- arch/x86/mm/pageattr.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) --------------------------- commit 883242dd0e5faaba041528a9a99f483f2a656c83 Author: Steven Rostedt <srostedt@redhat.com> Date: Tue Oct 27 13:15:11 2009 -0400
tracing: allow to change permissions for text with dynamic ftrace enabled The commit 74e081797bd9d2a7d8005fe519e719df343a2ba8 x86-64: align RODATA kernel section to 2MB with CONFIG_DEBUG_RODATA prevents text sections from becoming read/write using set_memory_rw. The dynamic ftrace changes all text pages to read/write just before converting the calls to tracing to nops, and vice versa. I orginally just added a flag to allow this transaction when ftrace did the change, but I also found that when the CPA testing was running it would remove the read/write as well, and ftrace does not do the text conversion on boot up, and the CPA changes caused the dynamic tracer to fail on self tests. The current solution I have is to simply not to prevent change_page_attr from setting the RW bit for kernel text pages. Reported-by: Ingo Molnar <mingo@elte.hu> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index b494fc4..78d3168 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -279,7 +279,8 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, __pa((unsigned long)__end_rodata) >> PAGE_SHIFT)) pgprot_val(forbidden) |= _PAGE_RW; -#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) +#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) && \ + !defined(CONFIG_DYNAMIC_FTRACE) /* * Kernel text mappings for the large page aligned .rodata section * will be read-only. For the kernel identity mappings covering
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