From: Michael Jeanson mjeanson@efficios.com

mainline inclusion from mainline-v6.0-rc1 commit d1a997ba4c1bf65497d956aea90de42a6398f73a category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I69PT8

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit d1a997ba4c1bf65497d956aea90de42a6398f73a upstream.

When checking for libc rseq support in the library constructor, don't only depend on the symbols presence, check that the registration was completed.

This targets a scenario where the libc has rseq support but it is not wired for the current architecture in 'bits/rseq.h', we want to fallback to our internal registration mechanism.

Signed-off-by: Michael Jeanson mjeanson@efficios.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Link: https://lore.kernel.org/r/20220614154830.1367382-4-mjeanson@efficios.com Signed-off-by: rminmin rmm0811@gmail.com --- tools/testing/selftests/rseq/rseq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c index 986b9458efb2..4177f9507bbe 100644 --- a/tools/testing/selftests/rseq/rseq.c +++ b/tools/testing/selftests/rseq/rseq.c @@ -111,7 +111,8 @@ void rseq_init(void) libc_rseq_offset_p = dlsym(RTLD_NEXT, "__rseq_offset"); libc_rseq_size_p = dlsym(RTLD_NEXT, "__rseq_size"); libc_rseq_flags_p = dlsym(RTLD_NEXT, "__rseq_flags"); - if (libc_rseq_size_p && libc_rseq_offset_p && libc_rseq_flags_p) { + if (libc_rseq_size_p && libc_rseq_offset_p && libc_rseq_flags_p && + *libc_rseq_size_p != 0) { /* rseq registration owned by glibc */ rseq_offset = *libc_rseq_offset_p; rseq_size = *libc_rseq_size_p;