Messages in this thread Patches in this message | | | Date | Thu, 1 May 2014 10:56:44 +0530 | From | Vineet Gupta <> | Subject | kprobes broken in linux-next (was Re: [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist) |
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On Thursday 24 April 2014 04:28 PM, tip-bot for Masami Hiramatsu wrote: > Commit-ID: 376e242429bf8539ef39a080ac113c8799840b13 > Gitweb: http://git.kernel.org/tip/376e242429bf8539ef39a080ac113c8799840b13 > Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> > AuthorDate: Thu, 17 Apr 2014 17:17:05 +0900 > Committer: Ingo Molnar <mingo@kernel.org> > CommitDate: Thu, 24 Apr 2014 10:02:56 +0200 > > kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist > > Introduce NOKPROBE_SYMBOL() macro which builds a kprobes > blacklist at kernel build time. > ....
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index 146e4ff..40ceb3c 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -109,6 +109,14 @@ > #define BRANCH_PROFILE() > #endif > > +#ifdef CONFIG_KPROBES > +#define KPROBE_BLACKLIST() VMLINUX_SYMBOL(__start_kprobe_blacklist) = .; \ > + *(_kprobe_blacklist) \ > + VMLINUX_SYMBOL(__stop_kprobe_blacklist) = .; > +#else > +#define KPROBE_BLACKLIST() > +#endif > + > #ifdef CONFIG_EVENT_TRACING > #define FTRACE_EVENTS() . = ALIGN(8); \ > VMLINUX_SYMBOL(__start_ftrace_events) = .; \ > @@ -507,6 +515,7 @@ > *(.init.rodata) \ > FTRACE_EVENTS() \ > TRACE_SYSCALLS() \ > + KPROBE_BLACKLIST() \ > MEM_DISCARD(init.rodata) \ > CLK_OF_TABLES() \ > RESERVEDMEM_OF_TABLES() \
Linux-next fails to boot on ARC due to misaligned __start_kprobe_blacklist. Patch below fixes it.
------------------------> From c5afc4ebf9c1c094a260e2aaff6c5b3106063039 Mon Sep 17 00:00:00 2001 From: Vineet Gupta <vgupta@synopsys.com> Date: Thu, 1 May 2014 10:47:29 +0530 Subject: [PATCH] kprobes: Ensure blacklist data is aligned
ARC Linux (not supporting native unaligned access) was failing to boot because __start_kprobe_blacklist was not aligned.
This was because per generated vmlinux.lds it was emitted right next to .rodata with strings etc hence could be randomly unaligned.
Fix that by ensuring a word alignment. While 4 would suffice for 32bit arches and problem at hand, it is probably better to put 8.
| Path: (null) CPU: 0 PID: 1 Comm: swapper Not tainted | 3.15.0-rc3-next-20140430 #2 | task: 8f044000 ti: 8f01e000 task.ti: 8f01e000 | | [ECR ]: 0x00230400 => Misaligned r/w from 0x800fb0d3 | [EFA ]: 0x800fb0d3 | [BLINK ]: do_one_initcall+0x86/0x1bc | [ERET ]: init_kprobes+0x52/0x120
Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- include/asm-generic/vmlinux.lds.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 40ceb3ceba79..8e0204a68c74 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -110,7 +110,8 @@ #endif
#ifdef CONFIG_KPROBES -#define KPROBE_BLACKLIST() VMLINUX_SYMBOL(__start_kprobe_blacklist) = .; \ +#define KPROBE_BLACKLIST() . = ALIGN(8); \ + VMLINUX_SYMBOL(__start_kprobe_blacklist) = .; \ *(_kprobe_blacklist) \ VMLINUX_SYMBOL(__stop_kprobe_blacklist) = .; #else -- 1.8.3.2
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