FWIW, I'm pretty sure that the issue is around the use of O_DIRECT and alignment of memory. Note that in the call to pread64() , the buffer isn't 4KB aligned, which is usually required for O_DIRECT. I assume that this generates the error and the rest of the issue.
On Wed, Dec 16, 2020 at 11:17 PM Oren Eini (Ayende Rahien) < aye...@ayende.com> wrote: > Hi, > I'm getting a strange error when running Valgrind. > > --23266-- WARNING: Serious error when reading debug info > --23266-- When reading debug info from /tmp/db/test.txt: > --23266-- can't read file to inspect ELF header > > Note that the file in question is a data file, which I'm mmaping > > I can reproduce this using the following code: > https://gist.github.com/ayende/d65a7a3c06556d62c8fa0f88b04ea449 > > valgrind-3.16.1 & clang version 10.0.0-4ubuntu1 > > This seems to be related to mmaping a file, but I can't figure out exactly > why > > Running Valgrind under `strace` gives: > > mmap(0x4e4d000, 65536, PROT_READ, MAP_SHARED|MAP_FIXED, 3, 0) = > 0x4e4d000 > statx(3, "", AT_STATX_SYNC_AS_STAT|AT_EMPTY_PATH, STATX_ALL, > {stx_mask=STATX_ALL, stx_attributes=0, stx_mode=S_IFREG|0600, > stx_size=262144, ...}) = 0 > readlink("/proc/self/fd/3", "/tmp/db/test.txt", 4096) = 16 > statx(AT_FDCWD, "/tmp/db/test.txt", AT_STATX_SYNC_AS_STAT, STATX_ALL, > {stx_mask=STATX_ALL, stx_attributes=0, stx_mode=S_IFREG|0600, > stx_size=262144, ...}) = 0 > pread64(3, 0x10032c68a0, 1024, 0) = -1 EINVAL (Invalid argument) > getpid() = 23260 > write(1027, "--23260-- WARNING: Serious error"..., 57--23260-- > WARNING: Serious error when reading debug info > ) = 57 > getpid() = 23260 > write(1027, "--23260-- When reading debug inf"..., 57--23260-- When > reading debug info from /tmp/db/test.txt: > > So it looks like the `pread64()` code is failing, but I can't figure out > why that is the case, or why it would cause Valgrind to give this error. > Any ideas? > -- <https://ravendb.net/> *Oren Eini* *CEO / Hibernating Rhinos LTD <https://hibernatingrhinos.com/>* Mobile: 972-52-548-6969 Sales: sa...@ravendb.net Skype: ayenderahien Support: supp...@ravendb.net <https://www.facebook.com/pages/RavenDB/265907650186374> <https://twitter.com/ravendb> <https://www.linkedin.com/company/hibernating-rhinos-ltd-/> <https://ravendb.net/emailsignature/displayeventpage>
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