| Message ID | 20110118164633.GA12872@Krystal |
|---|---|
| State | RFC |
| Delegated to: | David Miller |
| Headers | show |
On Tue, 2011-01-18 at 11:46 -0500, Mathieu Desnoyers wrote: > * David Miller (davem@davemloft.net) wrote: > > From: David Miller <davem@davemloft.net> > > Date: Mon, 17 Jan 2011 22:00:39 -0800 (PST) > > > > > ftrace: Remove unnecessary alignment tag from ftrace_event_call. > > > > > > It's completely unnecessary and causes problems on platforms > > > where this tag down-aligns the structure's alignment. > > > > > > Signed-off-by: David S. Miller <davem@davemloft.net> > > ... > > > > Ok, unless we can explain why these alignments are needed at all, we > > should kill all of them: > > ftrace: linker script add missing struct align > > We should add the missing "STRUCT_ALIGN();" in > include/asm-generic/vmlinux.lds.h as a preliminary step to remove the ftrace > bogus structure alignments. Moving all STRUCT_ALIGN() for FTRACE_EVENTS() > and TRACE_SYSCALLS() into the definitions, so the alignment is only done if > these infrastructures are configured in. > > Also align TRACE_PRINTKS on 8 bytes to make sure the beginning of the section is > aligned on pointer size. If I can make it crash without the alignments and this fixes the issue, I'll apply both patches. Thanks, -- Steve > > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > --- > include/asm-generic/vmlinux.lds.h | 19 ++++++++++--------- > 1 file changed, 10 insertions(+), 9 deletions(-) > > Index: linux-2.6-lttng/include/asm-generic/vmlinux.lds.h > =================================================================== > --- linux-2.6-lttng.orig/include/asm-generic/vmlinux.lds.h > +++ linux-2.6-lttng/include/asm-generic/vmlinux.lds.h > @@ -107,7 +107,8 @@ > #endif > > #ifdef CONFIG_TRACE_BRANCH_PROFILING > -#define LIKELY_PROFILE() VMLINUX_SYMBOL(__start_annotated_branch_profile) = .; \ > +#define LIKELY_PROFILE() STRUCT_ALIGN(); \ > + VMLINUX_SYMBOL(__start_annotated_branch_profile) = .; \ > *(_ftrace_annotated_branch) \ > VMLINUX_SYMBOL(__stop_annotated_branch_profile) = .; > #else > @@ -115,7 +116,8 @@ > #endif > > #ifdef CONFIG_PROFILE_ALL_BRANCHES > -#define BRANCH_PROFILE() VMLINUX_SYMBOL(__start_branch_profile) = .; \ > +#define BRANCH_PROFILE() STRUCT_ALIGN(); \ > + VMLINUX_SYMBOL(__start_branch_profile) = .; \ > *(_ftrace_branch) \ > VMLINUX_SYMBOL(__stop_branch_profile) = .; > #else > @@ -123,7 +125,8 @@ > #endif > > #ifdef CONFIG_EVENT_TRACING > -#define FTRACE_EVENTS() VMLINUX_SYMBOL(__start_ftrace_events) = .; \ > +#define FTRACE_EVENTS() STRUCT_ALIGN(); \ > + VMLINUX_SYMBOL(__start_ftrace_events) = .; \ > *(_ftrace_events) \ > VMLINUX_SYMBOL(__stop_ftrace_events) = .; > #else > @@ -131,7 +134,8 @@ > #endif > > #ifdef CONFIG_TRACING > -#define TRACE_PRINTKS() VMLINUX_SYMBOL(__start___trace_bprintk_fmt) = .; \ > +#define TRACE_PRINTKS() . = ALIGN(8); \ > + VMLINUX_SYMBOL(__start___trace_bprintk_fmt) = .; \ > *(__trace_printk_fmt) /* Trace_printk fmt' pointer */ \ > VMLINUX_SYMBOL(__stop___trace_bprintk_fmt) = .; > #else > @@ -139,7 +143,8 @@ > #endif > > #ifdef CONFIG_FTRACE_SYSCALLS > -#define TRACE_SYSCALLS() VMLINUX_SYMBOL(__start_syscalls_metadata) = .; \ > +#define TRACE_SYSCALLS() STRUCT_ALIGN(); \ > + VMLINUX_SYMBOL(__start_syscalls_metadata) = .; \ > *(__syscalls_metadata) \ > VMLINUX_SYMBOL(__stop_syscalls_metadata) = .; > #else > @@ -169,11 +174,7 @@ > LIKELY_PROFILE() \ > BRANCH_PROFILE() \ > TRACE_PRINTKS() \ > - \ > - STRUCT_ALIGN(); \ > FTRACE_EVENTS() \ > - \ > - STRUCT_ALIGN(); \ > TRACE_SYSCALLS() > > /* > > > -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 2011-01-18 at 12:33 -0500, Steven Rostedt wrote: > On Tue, 2011-01-18 at 11:46 -0500, Mathieu Desnoyers wrote: > > Also align TRACE_PRINTKS on 8 bytes to make sure the beginning of the section is > > aligned on pointer size. > > If I can make it crash without the alignments and this fixes the issue, > I'll apply both patches. After applying David's patch, I do indeed get a crash. I'll now apply yours and see if it fixes the issue. -- Steve -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 2011-01-18 at 13:16 -0500, Steven Rostedt wrote: > On Tue, 2011-01-18 at 12:33 -0500, Steven Rostedt wrote: > > On Tue, 2011-01-18 at 11:46 -0500, Mathieu Desnoyers wrote: > > > > Also align TRACE_PRINTKS on 8 bytes to make sure the beginning of the section is > > > aligned on pointer size. > > > > If I can make it crash without the alignments and this fixes the issue, > > I'll apply both patches. > > After applying David's patch, I do indeed get a crash. I'll now apply > yours and see if it fixes the issue. Your patch doesn't seem to fix it either. I'll investigate this further. -- Steve -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
* Steven Rostedt (rostedt@goodmis.org) wrote: > On Tue, 2011-01-18 at 13:16 -0500, Steven Rostedt wrote: > > On Tue, 2011-01-18 at 12:33 -0500, Steven Rostedt wrote: > > > On Tue, 2011-01-18 at 11:46 -0500, Mathieu Desnoyers wrote: > > > > > > Also align TRACE_PRINTKS on 8 bytes to make sure the beginning of the section is > > > > aligned on pointer size. > > > > > > If I can make it crash without the alignments and this fixes the issue, > > > I'll apply both patches. > > > > After applying David's patch, I do indeed get a crash. I'll now apply > > yours and see if it fixes the issue. > > Your patch doesn't seem to fix it either. I'll investigate this further. I think David's patch missed kernel/trace/trace_export.c struct ftrace_event_call __used \ __attribute__((__aligned__(4))) \ __attribute__((section("_ftrace_events"))) event_##call = { \ and kernel/trace/trace.h: #define FTRACE_ENTRY(call, struct_name, id, tstruct, print) \ extern struct ftrace_event_call \ __attribute__((__aligned__(4))) event_##call; does it help if you remove these ? Mathieu > > -- Steve > >
On Tue, 2011-01-18 at 15:13 -0500, Mathieu Desnoyers wrote: > * Steven Rostedt (rostedt@goodmis.org) wrote: > > On Tue, 2011-01-18 at 13:16 -0500, Steven Rostedt wrote: > > > On Tue, 2011-01-18 at 12:33 -0500, Steven Rostedt wrote: > > > > On Tue, 2011-01-18 at 11:46 -0500, Mathieu Desnoyers wrote: > > > > > > > > Also align TRACE_PRINTKS on 8 bytes to make sure the beginning of the section is > > > > > aligned on pointer size. > > > > > > > > If I can make it crash without the alignments and this fixes the issue, > > > > I'll apply both patches. > > > > > > After applying David's patch, I do indeed get a crash. I'll now apply > > > yours and see if it fixes the issue. > > > > Your patch doesn't seem to fix it either. I'll investigate this further. > > I think David's patch missed kernel/trace/trace_export.c > > struct ftrace_event_call __used \ > __attribute__((__aligned__(4))) \ > __attribute__((section("_ftrace_events"))) event_##call = { \ > > and kernel/trace/trace.h: > > #define FTRACE_ENTRY(call, struct_name, id, tstruct, print) \ > extern struct ftrace_event_call \ > __attribute__((__aligned__(4))) event_##call; > > does it help if you remove these ? I doubt it, but I'll try it anyway. -- Steve -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: linux-2.6-lttng/include/asm-generic/vmlinux.lds.h =================================================================== --- linux-2.6-lttng.orig/include/asm-generic/vmlinux.lds.h +++ linux-2.6-lttng/include/asm-generic/vmlinux.lds.h @@ -107,7 +107,8 @@ #endif #ifdef CONFIG_TRACE_BRANCH_PROFILING -#define LIKELY_PROFILE() VMLINUX_SYMBOL(__start_annotated_branch_profile) = .; \ +#define LIKELY_PROFILE() STRUCT_ALIGN(); \ + VMLINUX_SYMBOL(__start_annotated_branch_profile) = .; \ *(_ftrace_annotated_branch) \ VMLINUX_SYMBOL(__stop_annotated_branch_profile) = .; #else @@ -115,7 +116,8 @@ #endif #ifdef CONFIG_PROFILE_ALL_BRANCHES -#define BRANCH_PROFILE() VMLINUX_SYMBOL(__start_branch_profile) = .; \ +#define BRANCH_PROFILE() STRUCT_ALIGN(); \ + VMLINUX_SYMBOL(__start_branch_profile) = .; \ *(_ftrace_branch) \ VMLINUX_SYMBOL(__stop_branch_profile) = .; #else @@ -123,7 +125,8 @@ #endif #ifdef CONFIG_EVENT_TRACING -#define FTRACE_EVENTS() VMLINUX_SYMBOL(__start_ftrace_events) = .; \ +#define FTRACE_EVENTS() STRUCT_ALIGN(); \ + VMLINUX_SYMBOL(__start_ftrace_events) = .; \ *(_ftrace_events) \ VMLINUX_SYMBOL(__stop_ftrace_events) = .; #else @@ -131,7 +134,8 @@ #endif #ifdef CONFIG_TRACING -#define TRACE_PRINTKS() VMLINUX_SYMBOL(__start___trace_bprintk_fmt) = .; \ +#define TRACE_PRINTKS() . = ALIGN(8); \ + VMLINUX_SYMBOL(__start___trace_bprintk_fmt) = .; \ *(__trace_printk_fmt) /* Trace_printk fmt' pointer */ \ VMLINUX_SYMBOL(__stop___trace_bprintk_fmt) = .; #else @@ -139,7 +143,8 @@ #endif #ifdef CONFIG_FTRACE_SYSCALLS -#define TRACE_SYSCALLS() VMLINUX_SYMBOL(__start_syscalls_metadata) = .; \ +#define TRACE_SYSCALLS() STRUCT_ALIGN(); \ + VMLINUX_SYMBOL(__start_syscalls_metadata) = .; \ *(__syscalls_metadata) \ VMLINUX_SYMBOL(__stop_syscalls_metadata) = .; #else @@ -169,11 +174,7 @@ LIKELY_PROFILE() \ BRANCH_PROFILE() \ TRACE_PRINTKS() \ - \ - STRUCT_ALIGN(); \ FTRACE_EVENTS() \ - \ - STRUCT_ALIGN(); \ TRACE_SYSCALLS() /*