Scott Graham 9ee48fb1be Revert "Use a relative address in .note.crashpad.info"
This reverts commit 95e97a32eba4d505ab9591e683d2147c441eea48.

Reason for revert: arm64 lto build

Original change's description:
> Use a relative address in .note.crashpad.info
> 
> The desc value in the note is now the offset of CRASHPAD_INFO_SYMBOL
> from desc.
> 
> Making this note writable can trigger a linker error resulting in
> the binary embedding .note.crashpad.info to be rejected by the
> kernel during program loading.
> 
> The error was observed with:
> GNU ld (GNU Binutils for Debian) 2.30
> clang version 4.0.1-10 (tags/RELEASE_401/final)
> Debian 4.17.17-1rodete2
> 
> When the note is made writable, crashpad_snapshot_test contains two
> PT_LOAD segments which map to the same page.
> 
> LOAD         0x0000000000000000 0x0000000000000000 0x0000000000000000
>              0x0000000000000258 0x0000000000000258  R      0x200000
> LOAD         0x0000000000000258 0x0000000000000258 0x0000000000000258
>              0x00000000002b84d8 0x00000000002b8950  RWE    0x200000
> 
> Executing this binary with the execv system call triggers a segfault
> during program loading (an error can't be returned because the original
> process vm has already been discarded).
> 
> I suspect (I haven't set up a debuggable kernel) the failure occurs
> while attempting to map the second load segment because its virtual
> address, 0x258, is in the same page as the first load segment.
> https://elixir.bootlin.com/linux/v4.17.17/source/fs/binfmt_elf.c#L380
> 
> The linker normally produces consecutive load segments where the second
> segment is loaded 0x200000 bytes after the first, which I think is the
> maximum expected page size. Modifying the test executable to load the
> second segment at 0x1258 (4096 byte page size) allows program loading
> to succeed (but of course crashes after control is given to it).
> 
> Bug: crashpad:260
> Change-Id: I2b9f1e66e98919138baef3da991a9710bd970dc4
> Reviewed-on: https://chromium-review.googlesource.com/c/1292232
> Reviewed-by: Scott Graham <scottmg@chromium.org>
> Reviewed-by: Mark Mentovai <mark@chromium.org>
> Commit-Queue: Joshua Peraza <jperaza@chromium.org>

TBR=scottmg@chromium.org,jperaza@chromium.org,mark@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: crashpad:260
Change-Id: I7a2c741e6b4c10d3e3b8be3213a8ce2cd93675f7
Reviewed-on: https://chromium-review.googlesource.com/c/1316372
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
2018-11-03 03:28:19 +00:00
..