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| author | Peter Zijlstra <peterz@infradead.org> | 2022-06-28 12:57:42 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-07-07 13:26:54 +0200 |
| commit | 38e0e4d04d4187c63d6b511396faae7db6a3cd9e (patch) | |
| tree | 034ad0348d402ac9cbd208f053d2e04be8eae2e9 | |
| parent | b57feed2cc2622ae14b2fa62f19e973e5e0a60cf (diff) | |
| download | lwn-38e0e4d04d4187c63d6b511396faae7db6a3cd9e.tar.gz lwn-38e0e4d04d4187c63d6b511396faae7db6a3cd9e.zip | |
x86/ibt, objtool: Don't discard text references from tracepoint section
On Tue, Jun 28, 2022 at 04:28:58PM +0800, Pengfei Xu wrote:
> # ./ftracetest
> === Ftrace unit tests ===
> [1] Basic trace file check [PASS]
> [2] Basic test for tracers [PASS]
> [3] Basic trace clock test [PASS]
> [4] Basic event tracing check [PASS]
> [5] Change the ringbuffer size [PASS]
> [6] Snapshot and tracing setting [PASS]
> [7] trace_pipe and trace_marker [PASS]
> [8] Test ftrace direct functions against tracers [UNRESOLVED]
> [9] Test ftrace direct functions against kprobes [UNRESOLVED]
> [10] Generic dynamic event - add/remove eprobe events [FAIL]
> [11] Generic dynamic event - add/remove kprobe events
>
> It 100% reproduced in step 11 and then missing ENDBR BUG generated:
> "
> [ 9332.752836] mmiotrace: enabled CPU7.
> [ 9332.788612] mmiotrace: disabled.
> [ 9337.103426] traps: Missing ENDBR: syscall_regfunc+0x0/0xb0
It turns out that while syscall_regfunc() does have an ENDBR when
generated, it gets sealed by objtool's .ibt_endbr_seal list.
Since the only text references to this function:
$ git grep syscall_regfunc
include/linux/tracepoint.h:extern int syscall_regfunc(void);
include/trace/events/syscalls.h: syscall_regfunc, syscall_unregfunc
include/trace/events/syscalls.h: syscall_regfunc, syscall_unregfunc
kernel/tracepoint.c:int syscall_regfunc(void)
appear in the __tracepoint section which is excluded by objtool.
Fixes: 3c6f9f77e618 ("objtool: Rework ibt and extricate from stack validation")
Reported-by: Pengfei Xu <pengfei.xu@intel.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/Yrrepdaow4F5kqG0@hirez.programming.kicks-ass.net
| -rw-r--r-- | tools/objtool/check.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 864bb9dd3584..57153e00349c 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3826,8 +3826,7 @@ static int validate_ibt(struct objtool_file *file) !strcmp(sec->name, "__bug_table") || !strcmp(sec->name, "__ex_table") || !strcmp(sec->name, "__jump_table") || - !strcmp(sec->name, "__mcount_loc") || - !strcmp(sec->name, "__tracepoints")) + !strcmp(sec->name, "__mcount_loc")) continue; list_for_each_entry(reloc, &sec->reloc->reloc_list, list) |