| Message ID | 20240723232543.18093-1-richard.henderson@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | gitlab-ci: Use -fno-sanitize=function in the clang-user job | expand |
On 24/07/2024 01.25, Richard Henderson wrote: > With -fsanitize=undefined, which implies -fsanitize=function, > clang will add a "type signature" before functions. > It accesses funcptr-8 and funcptr-4 to do so. > > The generated TCG prologue is directly on a page boundary, > so these accesses segfault. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> What happend to Akihiko Odaki's more generic patch: https://lore.kernel.org/qemu-devel/20240714-function-v1-1-cc2acb4171ba@daynix.com/ ? Paolo, you mentioned that you'd queue it, did this patch fell through the cracks? > Does anyone know why we're using --extra-cflags for the clang-user > and clang-system jobs, as opposed to --enable-sanitizers? I don't remember, but it was likely the -fno-sanitize-recover=undefined I guess. > It > certainly seems like regular users who use the normal configure > flag are going to run into this as well. Yes, we should merge Akihiko Odaki's patch for this reason. Thomas
On Wed, Jul 24, 2024 at 09:25:42AM +1000, Richard Henderson wrote: > With -fsanitize=undefined, which implies -fsanitize=function, > clang will add a "type signature" before functions. > It accesses funcptr-8 and funcptr-4 to do so. > > The generated TCG prologue is directly on a page boundary, > so these accesses segfault. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > > Does anyone know why we're using --extra-cflags for the clang-user > and clang-system jobs, as opposed to --enable-sanitizers? It > certainly seems like regular users who use the normal configure > flag are going to run into this as well. > > Anyway, this is why the clang-user job is failing at the momemnt. > I can only assume that changes to our docker file, or upstream > distro updates have pulled in a new compiler version, because this > wasn't failing in this way last week. Logs show the clang version didn't change, but it is possible the libubsan.so package changed, but we can't see package versions. I've sent a series that will make it easier to compare pacakge versions between new & historical jobs in future situations like this: https://lists.nongnu.org/archive/html/qemu-devel/2024-07/msg05749.html With regards, Daniel
On 7/24/24 20:52, Daniel P. Berrangé wrote: > On Wed, Jul 24, 2024 at 09:25:42AM +1000, Richard Henderson wrote: >> With -fsanitize=undefined, which implies -fsanitize=function, >> clang will add a "type signature" before functions. >> It accesses funcptr-8 and funcptr-4 to do so. >> >> The generated TCG prologue is directly on a page boundary, >> so these accesses segfault. >> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> >> --- >> >> Does anyone know why we're using --extra-cflags for the clang-user >> and clang-system jobs, as opposed to --enable-sanitizers? It >> certainly seems like regular users who use the normal configure >> flag are going to run into this as well. >> >> Anyway, this is why the clang-user job is failing at the momemnt. >> I can only assume that changes to our docker file, or upstream >> distro updates have pulled in a new compiler version, because this >> wasn't failing in this way last week. > > Logs show the clang version didn't change, but it is possible the > libubsan.so package changed, but we can't see package versions. But the code generation definitely did -- the segv is right at the indirect function call to the (generated) tcg prologue. The library is not involved at all. > I've sent a series that will make it easier to compare pacakge > versions between new & historical jobs in future situations like > this: > > https://lists.nongnu.org/archive/html/qemu-devel/2024-07/msg05749.html Nice. r~
On 7/24/24 16:08, Thomas Huth wrote: > On 24/07/2024 01.25, Richard Henderson wrote: >> With -fsanitize=undefined, which implies -fsanitize=function, >> clang will add a "type signature" before functions. >> It accesses funcptr-8 and funcptr-4 to do so. >> >> The generated TCG prologue is directly on a page boundary, >> so these accesses segfault. >> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > > What happend to Akihiko Odaki's more generic patch: > > > https://lore.kernel.org/qemu-devel/20240714-function-v1-1-cc2acb4171ba@daynix.com/ > > ? This patch does not work: https://gitlab.com/qemu-project/qemu/-/jobs/7432239478/viewer#L4956 I presume this is an argument ordering issue vs --extra-cflags. r~
On 26/07/2024 01.33, Richard Henderson wrote: > On 7/24/24 16:08, Thomas Huth wrote: >> On 24/07/2024 01.25, Richard Henderson wrote: >>> With -fsanitize=undefined, which implies -fsanitize=function, >>> clang will add a "type signature" before functions. >>> It accesses funcptr-8 and funcptr-4 to do so. >>> >>> The generated TCG prologue is directly on a page boundary, >>> so these accesses segfault. >>> >>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> >> >> What happend to Akihiko Odaki's more generic patch: >> >> >> https://lore.kernel.org/qemu-devel/20240714-function-v1-1-cc2acb4171ba@daynix.com/ >> >> ? > > This patch does not work: > > https://gitlab.com/qemu-project/qemu/-/jobs/7432239478/viewer#L4956 > > I presume this is an argument ordering issue vs --extra-cflags. Ok, then we should definitely go with your patch to fix the job now. ... and I just saw that you already applied it
diff --git a/.gitlab-ci.d/buildtest.yml b/.gitlab-ci.d/buildtest.yml index e3a0758bd9..aa32782405 100644 --- a/.gitlab-ci.d/buildtest.yml +++ b/.gitlab-ci.d/buildtest.yml @@ -444,6 +444,7 @@ clang-user: CONFIGURE_ARGS: --cc=clang --cxx=clang++ --disable-system --target-list-exclude=alpha-linux-user,microblazeel-linux-user,aarch64_be-linux-user,i386-linux-user,m68k-linux-user,mipsn32el-linux-user,xtensaeb-linux-user --extra-cflags=-fsanitize=undefined --extra-cflags=-fno-sanitize-recover=undefined + --extra-cflags=-fno-sanitize=function MAKE_CHECK_ARGS: check-unit check-tcg # Set LD_JOBS=1 because this requires LTO and ld consumes a large amount of memory.
With -fsanitize=undefined, which implies -fsanitize=function, clang will add a "type signature" before functions. It accesses funcptr-8 and funcptr-4 to do so. The generated TCG prologue is directly on a page boundary, so these accesses segfault. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- Does anyone know why we're using --extra-cflags for the clang-user and clang-system jobs, as opposed to --enable-sanitizers? It certainly seems like regular users who use the normal configure flag are going to run into this as well. Anyway, this is why the clang-user job is failing at the momemnt. I can only assume that changes to our docker file, or upstream distro updates have pulled in a new compiler version, because this wasn't failing in this way last week. r~ --- .gitlab-ci.d/buildtest.yml | 1 + 1 file changed, 1 insertion(+)