| Message ID | 20170306123150.99386-3-roger.pau@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
>>> On 06.03.17 at 13:31, <roger.pau@citrix.com> wrote: > There seems to be some weird bug in clang 4.0 that prevents xsm_pmu_op from > working as expected, and vpmu.o ends up with a reference to > __xsm_action_mismatch_detected which makes the build fail: > > [...] > ld -melf_x86_64_fbsd -T xen.lds -N prelink.o \ > xen/common/symbols-dummy.o -o xen/.xen-syms.0 > prelink.o: In function `xsm_default_action': > xen/include/xsm/dummy.h:80: undefined reference to > `__xsm_action_mismatch_detected' > xen/xen/include/xsm/dummy.h:80: relocation truncated to fit: R_X86_64_PC32 > against undefined symbol `__xsm_action_mismatch_detected' > ld: xen/xen/.xen-syms.0: hidden symbol `__xsm_action_mismatch_detected' > isn't defined > > Then doing a search in the objects files: > > # find xen/ -type f -name '*.o' -print0 | xargs -0 bash -c \ > 'for filename; do nm "$filename" | \ > grep -q __xsm_action_mismatch_detected && echo "$filename"; done' bash > xen/arch/x86/prelink.o > xen/arch/x86/cpu/vpmu.o > xen/arch/x86/cpu/built_in.o > xen/arch/x86/built_in.o > > The current patch is the only way I've found to fix this so far, by simply > moving the XSM_PRIV check into the default case in xsm_pmu_op. This also fixes > the behavior of do_xenpmu_op, which will now return -EINVAL for unknown > XENPMU_* operations, instead of -EPERM when called by a privileged domain. Especially from this perspective I think the patch is fine (but also Cc-ing Boris), yet I still think the compilation aspect needs to be got to the bottom of, to have a complete picture in case the problem shows up in a slightly different way elsewhere. Did you report this to clang folks? Did they have any explanation of what's going on? Jan
On 03/06/2017 07:52 AM, Jan Beulich wrote: >>>> On 06.03.17 at 13:31, <roger.pau@citrix.com> wrote: >> There seems to be some weird bug in clang 4.0 that prevents xsm_pmu_op from >> working as expected, and vpmu.o ends up with a reference to >> __xsm_action_mismatch_detected which makes the build fail: >> >> [...] >> ld -melf_x86_64_fbsd -T xen.lds -N prelink.o \ >> xen/common/symbols-dummy.o -o xen/.xen-syms.0 >> prelink.o: In function `xsm_default_action': >> xen/include/xsm/dummy.h:80: undefined reference to >> `__xsm_action_mismatch_detected' >> xen/xen/include/xsm/dummy.h:80: relocation truncated to fit: R_X86_64_PC32 >> against undefined symbol `__xsm_action_mismatch_detected' >> ld: xen/xen/.xen-syms.0: hidden symbol `__xsm_action_mismatch_detected' >> isn't defined >> >> Then doing a search in the objects files: >> >> # find xen/ -type f -name '*.o' -print0 | xargs -0 bash -c \ >> 'for filename; do nm "$filename" | \ >> grep -q __xsm_action_mismatch_detected && echo "$filename"; done' bash >> xen/arch/x86/prelink.o >> xen/arch/x86/cpu/vpmu.o >> xen/arch/x86/cpu/built_in.o >> xen/arch/x86/built_in.o >> >> The current patch is the only way I've found to fix this so far, by simply >> moving the XSM_PRIV check into the default case in xsm_pmu_op. This also fixes >> the behavior of do_xenpmu_op, which will now return -EINVAL for unknown >> XENPMU_* operations, instead of -EPERM when called by a privileged domain. How will these changes make do_xenpmu_op() return -EINVAL? -boris > Especially from this perspective I think the patch is fine (but also > Cc-ing Boris), yet I still think the compilation aspect needs to be got > to the bottom of, to have a complete picture in case the problem > shows up in a slightly different way elsewhere. Did you report this > to clang folks? Did they have any explanation of what's going on? > > Jan >
>>> On 06.03.17 at 15:42, <boris.ostrovsky@oracle.com> wrote: > On 03/06/2017 07:52 AM, Jan Beulich wrote: >>>>> On 06.03.17 at 13:31, <roger.pau@citrix.com> wrote: >>> There seems to be some weird bug in clang 4.0 that prevents xsm_pmu_op from >>> working as expected, and vpmu.o ends up with a reference to >>> __xsm_action_mismatch_detected which makes the build fail: >>> >>> [...] >>> ld -melf_x86_64_fbsd -T xen.lds -N prelink.o \ >>> xen/common/symbols-dummy.o -o xen/.xen-syms.0 >>> prelink.o: In function `xsm_default_action': >>> xen/include/xsm/dummy.h:80: undefined reference to >>> `__xsm_action_mismatch_detected' >>> xen/xen/include/xsm/dummy.h:80: relocation truncated to fit: R_X86_64_PC32 >>> against undefined symbol `__xsm_action_mismatch_detected' >>> ld: xen/xen/.xen-syms.0: hidden symbol `__xsm_action_mismatch_detected' >>> isn't defined >>> >>> Then doing a search in the objects files: >>> >>> # find xen/ -type f -name '*.o' -print0 | xargs -0 bash -c \ >>> 'for filename; do nm "$filename" | \ >>> grep -q __xsm_action_mismatch_detected && echo "$filename"; done' bash >>> xen/arch/x86/prelink.o >>> xen/arch/x86/cpu/vpmu.o >>> xen/arch/x86/cpu/built_in.o >>> xen/arch/x86/built_in.o >>> >>> The current patch is the only way I've found to fix this so far, by simply >>> moving the XSM_PRIV check into the default case in xsm_pmu_op. This also fixes >>> the behavior of do_xenpmu_op, which will now return -EINVAL for unknown >>> XENPMU_* operations, instead of -EPERM when called by a privileged domain. > > How will these changes make do_xenpmu_op() return -EINVAL? Since the XSM check no longer returns -EPERM, the handling inside do_vpmu_op() will now reach the default case there. Jan
On 03/06/2017 09:54 AM, Jan Beulich wrote: >>>> On 06.03.17 at 15:42, <boris.ostrovsky@oracle.com> wrote: >> On 03/06/2017 07:52 AM, Jan Beulich wrote: >>>>>> On 06.03.17 at 13:31, <roger.pau@citrix.com> wrote: >>>> There seems to be some weird bug in clang 4.0 that prevents xsm_pmu_op from >>>> working as expected, and vpmu.o ends up with a reference to >>>> __xsm_action_mismatch_detected which makes the build fail: >>>> >>>> [...] >>>> ld -melf_x86_64_fbsd -T xen.lds -N prelink.o \ >>>> xen/common/symbols-dummy.o -o xen/.xen-syms.0 >>>> prelink.o: In function `xsm_default_action': >>>> xen/include/xsm/dummy.h:80: undefined reference to >>>> `__xsm_action_mismatch_detected' >>>> xen/xen/include/xsm/dummy.h:80: relocation truncated to fit: R_X86_64_PC32 >>>> against undefined symbol `__xsm_action_mismatch_detected' >>>> ld: xen/xen/.xen-syms.0: hidden symbol `__xsm_action_mismatch_detected' >>>> isn't defined >>>> >>>> Then doing a search in the objects files: >>>> >>>> # find xen/ -type f -name '*.o' -print0 | xargs -0 bash -c \ >>>> 'for filename; do nm "$filename" | \ >>>> grep -q __xsm_action_mismatch_detected && echo "$filename"; done' bash >>>> xen/arch/x86/prelink.o >>>> xen/arch/x86/cpu/vpmu.o >>>> xen/arch/x86/cpu/built_in.o >>>> xen/arch/x86/built_in.o >>>> >>>> The current patch is the only way I've found to fix this so far, by simply >>>> moving the XSM_PRIV check into the default case in xsm_pmu_op. This also fixes >>>> the behavior of do_xenpmu_op, which will now return -EINVAL for unknown >>>> XENPMU_* operations, instead of -EPERM when called by a privileged domain. >> How will these changes make do_xenpmu_op() return -EINVAL? > Since the XSM check no longer returns -EPERM, the handling inside > do_vpmu_op() will now reach the default case there. Oh, I was staring at xsm_default_action() and trying to see where -EINVAL would be coming from. Sorry for the noise. -boris
On Mon, Mar 06, 2017 at 05:52:14AM -0700, Jan Beulich wrote: > >>> On 06.03.17 at 13:31, <roger.pau@citrix.com> wrote: > > There seems to be some weird bug in clang 4.0 that prevents xsm_pmu_op from > > working as expected, and vpmu.o ends up with a reference to > > __xsm_action_mismatch_detected which makes the build fail: > > > > [...] > > ld -melf_x86_64_fbsd -T xen.lds -N prelink.o \ > > xen/common/symbols-dummy.o -o xen/.xen-syms.0 > > prelink.o: In function `xsm_default_action': > > xen/include/xsm/dummy.h:80: undefined reference to > > `__xsm_action_mismatch_detected' > > xen/xen/include/xsm/dummy.h:80: relocation truncated to fit: R_X86_64_PC32 > > against undefined symbol `__xsm_action_mismatch_detected' > > ld: xen/xen/.xen-syms.0: hidden symbol `__xsm_action_mismatch_detected' > > isn't defined > > > > Then doing a search in the objects files: > > > > # find xen/ -type f -name '*.o' -print0 | xargs -0 bash -c \ > > 'for filename; do nm "$filename" | \ > > grep -q __xsm_action_mismatch_detected && echo "$filename"; done' bash > > xen/arch/x86/prelink.o > > xen/arch/x86/cpu/vpmu.o > > xen/arch/x86/cpu/built_in.o > > xen/arch/x86/built_in.o > > > > The current patch is the only way I've found to fix this so far, by simply > > moving the XSM_PRIV check into the default case in xsm_pmu_op. This also fixes > > the behavior of do_xenpmu_op, which will now return -EINVAL for unknown > > XENPMU_* operations, instead of -EPERM when called by a privileged domain. > > Especially from this perspective I think the patch is fine (but also > Cc-ing Boris), yet I still think the compilation aspect needs to be got > to the bottom of, to have a complete picture in case the problem > shows up in a slightly different way elsewhere. Did you report this > to clang folks? Did they have any explanation of what's going on? I've just reported this upstream, for the record the ticket is at: http://bugs.llvm.org/show_bug.cgi?id=32150 Roger.
On 03/06/2017 07:31 AM, Roger Pau Monne wrote: > There seems to be some weird bug in clang 4.0 that prevents xsm_pmu_op from > working as expected, and vpmu.o ends up with a reference to > __xsm_action_mismatch_detected which makes the build fail: > > [...] > ld -melf_x86_64_fbsd -T xen.lds -N prelink.o \ > xen/common/symbols-dummy.o -o xen/.xen-syms.0 > prelink.o: In function `xsm_default_action': > xen/include/xsm/dummy.h:80: undefined reference to `__xsm_action_mismatch_detected' > xen/xen/include/xsm/dummy.h:80: relocation truncated to fit: R_X86_64_PC32 against undefined symbol `__xsm_action_mismatch_detected' > ld: xen/xen/.xen-syms.0: hidden symbol `__xsm_action_mismatch_detected' isn't defined > > Then doing a search in the objects files: > > # find xen/ -type f -name '*.o' -print0 | xargs -0 bash -c \ > 'for filename; do nm "$filename" | \ > grep -q __xsm_action_mismatch_detected && echo "$filename"; done' bash > xen/arch/x86/prelink.o > xen/arch/x86/cpu/vpmu.o > xen/arch/x86/cpu/built_in.o > xen/arch/x86/built_in.o > > The current patch is the only way I've found to fix this so far, by simply > moving the XSM_PRIV check into the default case in xsm_pmu_op. This also fixes > the behavior of do_xenpmu_op, which will now return -EINVAL for unknown > XENPMU_* operations, instead of -EPERM when called by a privileged domain. > > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> This also looks like a good patch for backporting. The best alternative I can think of is to disable the mismatch detection in non-DEBUG builds, but I'd rather not do that unless this problem expands more than it has.
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h index 4b27ae7..ff73039 100644 --- a/xen/include/xsm/dummy.h +++ b/xen/include/xsm/dummy.h @@ -682,18 +682,13 @@ static XSM_INLINE int xsm_pmu_op (XSM_DEFAULT_ARG struct domain *d, unsigned int XSM_ASSERT_ACTION(XSM_OTHER); switch ( op ) { - case XENPMU_mode_set: - case XENPMU_mode_get: - case XENPMU_feature_set: - case XENPMU_feature_get: - return xsm_default_action(XSM_PRIV, d, current->domain); case XENPMU_init: case XENPMU_finish: case XENPMU_lvtpc_set: case XENPMU_flush: return xsm_default_action(XSM_HOOK, d, current->domain); default: - return -EPERM; + return xsm_default_action(XSM_PRIV, d, current->domain); } }
There seems to be some weird bug in clang 4.0 that prevents xsm_pmu_op from working as expected, and vpmu.o ends up with a reference to __xsm_action_mismatch_detected which makes the build fail: [...] ld -melf_x86_64_fbsd -T xen.lds -N prelink.o \ xen/common/symbols-dummy.o -o xen/.xen-syms.0 prelink.o: In function `xsm_default_action': xen/include/xsm/dummy.h:80: undefined reference to `__xsm_action_mismatch_detected' xen/xen/include/xsm/dummy.h:80: relocation truncated to fit: R_X86_64_PC32 against undefined symbol `__xsm_action_mismatch_detected' ld: xen/xen/.xen-syms.0: hidden symbol `__xsm_action_mismatch_detected' isn't defined Then doing a search in the objects files: # find xen/ -type f -name '*.o' -print0 | xargs -0 bash -c \ 'for filename; do nm "$filename" | \ grep -q __xsm_action_mismatch_detected && echo "$filename"; done' bash xen/arch/x86/prelink.o xen/arch/x86/cpu/vpmu.o xen/arch/x86/cpu/built_in.o xen/arch/x86/built_in.o The current patch is the only way I've found to fix this so far, by simply moving the XSM_PRIV check into the default case in xsm_pmu_op. This also fixes the behavior of do_xenpmu_op, which will now return -EINVAL for unknown XENPMU_* operations, instead of -EPERM when called by a privileged domain. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- Cc: Daniel De Graaf <dgdegra@tycho.nsa.gov> --- xen/include/xsm/dummy.h | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)