| Message ID | 20241210224435.15206-1-rananta@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | selftests/rseq: Fix rseq for cases without glibc support | expand |
On 12/10/24 15:44, Raghavendra Rao Ananta wrote: > Currently the rseq constructor, rseq_init(), assumes that glibc always > has the support for rseq symbols (__rseq_size for instance). However, > glibc supports rseq from version 2.35 onwards. As a result, for the > systems that run glibc less than 2.35, the global rseq_size remains > initialized to -1U. When a thread then tries to register for rseq, > get_rseq_min_alloc_size() would end up returning -1U, which is > incorrect. Hence, initialize rseq_size for the cases where glibc doesn't > have the support for rseq symbols. > > Cc: stable@vger.kernel.org > Fixes: 73a4f5a704a2 ("selftests/rseq: Fix mm_cid test failure") > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> > --- Applied to linux_kselftest next for Linux 6.14-rc1 after fixing the commit if for Fixes tag thanks, -- Shuah
On 2025-01-13 18:06, Shuah Khan wrote: > On 12/10/24 15:44, Raghavendra Rao Ananta wrote: >> Currently the rseq constructor, rseq_init(), assumes that glibc always >> has the support for rseq symbols (__rseq_size for instance). However, >> glibc supports rseq from version 2.35 onwards. As a result, for the >> systems that run glibc less than 2.35, the global rseq_size remains >> initialized to -1U. When a thread then tries to register for rseq, >> get_rseq_min_alloc_size() would end up returning -1U, which is >> incorrect. Hence, initialize rseq_size for the cases where glibc doesn't >> have the support for rseq symbols. >> >> Cc: stable@vger.kernel.org >> Fixes: 73a4f5a704a2 ("selftests/rseq: Fix mm_cid test failure") >> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> >> --- > > Applied to linux_kselftest next for Linux 6.14-rc1 after fixing the > commit if for Fixes tag Hi Shuah, I did not review nor ack this patch. I need to review it carefully to make sure it does not break anything else moving forward. Please wait before merging. Thanks, Mathieu > > thanks, > -- Shuah
On 2025-01-14 09:07, Mathieu Desnoyers wrote: > On 2025-01-13 18:06, Shuah Khan wrote: >> On 12/10/24 15:44, Raghavendra Rao Ananta wrote: >>> Currently the rseq constructor, rseq_init(), assumes that glibc always >>> has the support for rseq symbols (__rseq_size for instance). However, >>> glibc supports rseq from version 2.35 onwards. As a result, for the >>> systems that run glibc less than 2.35, the global rseq_size remains >>> initialized to -1U. When a thread then tries to register for rseq, >>> get_rseq_min_alloc_size() would end up returning -1U, which is >>> incorrect. Hence, initialize rseq_size for the cases where glibc doesn't >>> have the support for rseq symbols. >>> >>> Cc: stable@vger.kernel.org >>> Fixes: 73a4f5a704a2 ("selftests/rseq: Fix mm_cid test failure") >>> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> >>> --- >> >> Applied to linux_kselftest next for Linux 6.14-rc1 after fixing the >> commit if for Fixes tag > > Hi Shuah, > > I did not review nor ack this patch. I need to review it carefully > to make sure it does not break anything else moving forward. > > Please wait before merging. I am preparing an alternative fix which keeps the selftests code in sync with librseq. Thanks, Mathieu > > Thanks, > > Mathieu > >> >> thanks, >> -- Shuah >
On 1/14/25 07:27, Mathieu Desnoyers wrote: > On 2025-01-14 09:07, Mathieu Desnoyers wrote: >> On 2025-01-13 18:06, Shuah Khan wrote: >>> On 12/10/24 15:44, Raghavendra Rao Ananta wrote: >>>> Currently the rseq constructor, rseq_init(), assumes that glibc always >>>> has the support for rseq symbols (__rseq_size for instance). However, >>>> glibc supports rseq from version 2.35 onwards. As a result, for the >>>> systems that run glibc less than 2.35, the global rseq_size remains >>>> initialized to -1U. When a thread then tries to register for rseq, >>>> get_rseq_min_alloc_size() would end up returning -1U, which is >>>> incorrect. Hence, initialize rseq_size for the cases where glibc doesn't >>>> have the support for rseq symbols. >>>> >>>> Cc: stable@vger.kernel.org >>>> Fixes: 73a4f5a704a2 ("selftests/rseq: Fix mm_cid test failure") >>>> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> >>>> --- >>> >>> Applied to linux_kselftest next for Linux 6.14-rc1 after fixing the >>> commit if for Fixes tag >> >> Hi Shuah, >> >> I did not review nor ack this patch. I need to review it carefully >> to make sure it does not break anything else moving forward. >> >> Please wait before merging. > > I am preparing an alternative fix which keeps the selftests > code in sync with librseq. > Sorry for the mixup. I will go drop this now. thanks, -- Shuah
diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c index 5b9772cdf265..9eb5356f25fa 100644 --- a/tools/testing/selftests/rseq/rseq.c +++ b/tools/testing/selftests/rseq/rseq.c @@ -142,6 +142,16 @@ unsigned int get_rseq_kernel_feature_size(void) return ORIG_RSEQ_FEATURE_SIZE; } +static void set_default_rseq_size(void) +{ + unsigned int rseq_kernel_feature_size = get_rseq_kernel_feature_size(); + + if (rseq_kernel_feature_size < ORIG_RSEQ_ALLOC_SIZE) + rseq_size = rseq_kernel_feature_size; + else + rseq_size = ORIG_RSEQ_ALLOC_SIZE; +} + int rseq_register_current_thread(void) { int rc; @@ -219,12 +229,7 @@ void rseq_init(void) fallthrough; case ORIG_RSEQ_ALLOC_SIZE: { - unsigned int rseq_kernel_feature_size = get_rseq_kernel_feature_size(); - - if (rseq_kernel_feature_size < ORIG_RSEQ_ALLOC_SIZE) - rseq_size = rseq_kernel_feature_size; - else - rseq_size = ORIG_RSEQ_ALLOC_SIZE; + set_default_rseq_size(); break; } default: @@ -239,8 +244,10 @@ void rseq_init(void) rseq_size = 0; return; } + rseq_offset = (void *)&__rseq_abi - rseq_thread_pointer(); rseq_flags = 0; + set_default_rseq_size(); } static __attribute__((destructor))
Currently the rseq constructor, rseq_init(), assumes that glibc always has the support for rseq symbols (__rseq_size for instance). However, glibc supports rseq from version 2.35 onwards. As a result, for the systems that run glibc less than 2.35, the global rseq_size remains initialized to -1U. When a thread then tries to register for rseq, get_rseq_min_alloc_size() would end up returning -1U, which is incorrect. Hence, initialize rseq_size for the cases where glibc doesn't have the support for rseq symbols. Cc: stable@vger.kernel.org Fixes: 73a4f5a704a2 ("selftests/rseq: Fix mm_cid test failure") Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> --- tools/testing/selftests/rseq/rseq.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37