2019-07-11 02:41:32

by Mao Han

[permalink] [raw]
Subject: [PATCH 1/1] riscv: Fix perf record without libelf support

This patch fix following perf record error by linking vdso.so with
build id.

perf.data perf.data.old
[ perf record: Woken up 1 times to write data ]
free(): double free detected in tcache 2
Aborted

perf record use filename__read_build_id(util/symbol-minimal.c) to get
build id when libelf is not supported. When vdso.so is linked without
build id, the section size of PT_NOTE will be zero, buf size will
realloc to zero and cause memory corruption.

Signed-off-by: Mao Han <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
---
arch/riscv/kernel/vdso/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index f1d6ffe..49a5852 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -37,7 +37,7 @@ $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
# these symbols in the kernel code rather than hand-coded addresses.

SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
- -Wl,--hash-style=both
+ -Wl,--build-id -Wl,--hash-style=both
$(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE
$(call if_changed,vdsold)

--
2.7.4


2019-07-25 21:14:16

by Paul Walmsley

[permalink] [raw]
Subject: Re: [PATCH 1/1] riscv: Fix perf record without libelf support

On Thu, 11 Jul 2019, Mao Han wrote:

> This patch fix following perf record error by linking vdso.so with
> build id.
>
> perf.data perf.data.old
> [ perf record: Woken up 1 times to write data ]
> free(): double free detected in tcache 2
> Aborted
>
> perf record use filename__read_build_id(util/symbol-minimal.c) to get
> build id when libelf is not supported. When vdso.so is linked without
> build id, the section size of PT_NOTE will be zero, buf size will
> realloc to zero and cause memory corruption.
>
> Signed-off-by: Mao Han <[email protected]>
> Cc: Paul Walmsley <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Albert Ou <[email protected]>

Thanks, queued for v5.3-rc.

Also: thanks for your patience on the perf callchain patches.


- Paul