Hi Matthew, > -----Original Message----- > From: Gcc-patches <gcc-patches-boun...@gcc.gnu.org> On Behalf Of > Matthew Malcomson via Gcc-patches > Sent: 24 November 2020 15:47 > To: gcc-patches@gcc.gnu.org > Cc: Richard Sandiford <richard.sandif...@arm.com> > Subject: libsanitizer: Hwasan reporting check for dladdr failing > > Hello there, > > This is the compiler-rt patch I'd like to cherry-pick so that the hwasan tests > pass. > > It is in LLVM as commit 83ac18205ec69a00ac2be3b603bc3a61293fbe89. > > Ok for trunk? > > Also is the libhwasan library merge from the below email OK for trunk? > https://gcc.gnu.org/pipermail/gcc-patches/2020-November/558999.html > (Note I would also add a line to README.gcc mentioning compiler- > rt/lib/hwasan > on top of the changes in that patch). > > I would guess so, but wasn't certain the OK had ever been said anywhere.
I believe merges from an upstream are generally considered pre-approved. In any case, I see that merge committed as 98f792ff538109c71d85ab2a61461cd090f3b9f3 Thanks, Kyrill > > Regards, > Matthew > > ------------------------- > > > In `GetGlobalSizeFromDescriptor` we use `dladdr` to get info on the the > current address. `dladdr` returns 0 if it failed. > During testing on Linux this returned 0 to indicate failure, and > populated the `info` structure with a NULL pointer which was > dereferenced later. > > This patch checks for `dladdr` returning 0, and in that case returns 0 > from `GetGlobalSizeFromDescriptor` to indicate failure of identifying > the address. > > This occurs when `GetModuleNameAndOffsetForPC` succeeds for some > address > not in a dynamically loaded library. One example is when the found > "module" is '[stack]' having come from parsing /proc/self/maps. > > Cherry-pick from 83ac18205ec69a00ac2be3b603bc3a61293fbe89. > > Differential Revision: https://reviews.llvm.org/D91344 > > > ############### Attachment also inlined for ease of reply > ############### > > > diff --git a/libsanitizer/hwasan/hwasan_report.cpp > b/libsanitizer/hwasan/hwasan_report.cpp > index > 0be7deeaee1a0bd523d9e0fe1dc3b1311b3920e2..894a149775f291bae9cad8 > 33b1ac54914212f405 100644 > --- a/libsanitizer/hwasan/hwasan_report.cpp > +++ b/libsanitizer/hwasan/hwasan_report.cpp > @@ -254,7 +254,8 @@ static bool TagsEqual(tag_t tag, tag_t *tag_ptr) { > static uptr GetGlobalSizeFromDescriptor(uptr ptr) { > // Find the ELF object that this global resides in. > Dl_info info; > - dladdr(reinterpret_cast<void *>(ptr), &info); > + if (dladdr(reinterpret_cast<void *>(ptr), &info) == 0) > + return 0; > auto *ehdr = reinterpret_cast<const ElfW(Ehdr) *>(info.dli_fbase); > auto *phdr_begin = reinterpret_cast<const ElfW(Phdr) *>( > reinterpret_cast<const u8 *>(ehdr) + ehdr->e_phoff);
