bpo-32962: Fix test_gdb failure in debug build with -mcet -fcf-protection -O0#6754
Conversation
Member
|
Reminder for reviewers: test_gdb is not run on Travis CI. Tests must be run manually before merging such change. |
Contributor
|
Also in order to test the change, gcc >= 8 is required. |
ghost
changed the title
-mcet -fcf-protection -O0…H-6754) When Python is built with the intel control-flow protection flags, -mcet -fcf-protection, gdb is not able to read the stack without actually jumping inside the function. This means an extra 'next' command is required to make the $pc (program counter) enter the function and make the stack of the function exposed to gdb.
vstinner
reviewed
Jun 14, 2018
Lib/test/test_gdb.py
Outdated
| # ignore all warnings | ||
| 'warning: ', | ||
| # See #32962 | ||
| 'Python Exception', |
Member
There was a problem hiding this comment.
Hum, this is not a good idea to ignore bugs :-( Please revert this change.
My #7693 should fix this bug.
vstinner
reviewed
Jun 14, 2018
|
|
||
| if cmds_after_breakpoint: | ||
| commands += cmds_after_breakpoint | ||
| commands += ['next'] + cmds_after_breakpoint |
Member
There was a problem hiding this comment.
Please add a comment explaining why next is needed. Something like:
# bpo-32962: When Python is compiled with -mcet -fcf-protection,
# arguments are unusable before running the first instruction
# of the function entry point.
vstinner
reviewed
Jun 14, 2018
| # Verify with "py-bt": | ||
| gdb_output = self.get_stack_trace(cmd, | ||
| cmds_after_breakpoint=['break wrapper_call', 'continue', 'py-bt']) | ||
| cmds_after_breakpoint=['break wrapper_call', 'continue', 'next', 'py-bt']) |
vstinner
approved these changes
Jun 15, 2018
Member
vstinner
left a comment
vstinner
left a comment
There was a problem hiding this comment.
LGTM, just two minor remarks on comments.
Lib/test/test_gdb.py
Outdated
|
|
||
| # bpo-32962: When Python is compiled with -mcet -fcf-protection, | ||
| # arguments are unusable before running the first instruction | ||
| # of the function entry point. Next makes the required first step. |
Member
There was a problem hiding this comment.
Would you mind to replace Next with >The 'next' command< to make it more explicit?
Move also the comment inside the if block.
Lib/test/test_gdb.py
Outdated
| l = MyList() | ||
| ''') | ||
| # bpo-32962: same case as in get_stack_trace(): | ||
| # we need one extra step in order to read arguments |
Member
There was a problem hiding this comment.
Replace "we need one extra step" with "we need 'next' extra command".
|
@vstinner: Please replace |
vstinner
added a commit
that referenced
this pull request
Jun 15, 2018
…H-7710) * bpo-32962: python-gdb catchs ValueError on read_var() (GH-7692) python-gdb now catchs ValueError on read_var(): when Python has no debug symbols for example. (cherry picked from commit 019d33b) * bpo-32962: python-gdb catchs UnicodeDecodeError (GH-7693) python-gdb now catchs UnicodeDecodeError exceptions when calling string(). (cherry picked from commit d22fc0b) * bpo-32962: Fix test_gdb failure in debug build with -mcet -fcf-protection -O0 (GH-6754) When Python is built with the intel control-flow protection flags, -mcet -fcf-protection, gdb is not able to read the stack without actually jumping inside the function. This means an extra 'next' command is required to make the $pc (program counter) enter the function and make the stack of the function exposed to gdb. (cherry picked from commit 9b7c74c)
vstinner
added a commit
that referenced
this pull request
Jun 15, 2018
… (GH-7711) * bpo-32962: python-gdb catchs ValueError on read_var() (GH-7692) python-gdb now catchs ValueError on read_var(): when Python has no debug symbols for example. (cherry picked from commit 019d33b) * bpo-32962: python-gdb catchs UnicodeDecodeError (GH-7693) python-gdb now catchs UnicodeDecodeError exceptions when calling string(). (cherry picked from commit d22fc0b) * bpo-32962: Fix test_gdb failure in debug build with -mcet -fcf-protection -O0 (GH-6754) When Python is built with the intel control-flow protection flags, -mcet -fcf-protection, gdb is not able to read the stack without actually jumping inside the function. This means an extra 'next' command is required to make the $pc (program counter) enter the function and make the stack of the function exposed to gdb. (cherry picked from commit 9b7c74c) (cherry picked from commit ca4cb84)
vstinner
added a commit
that referenced
this pull request
Jun 15, 2018
vstinner
added a commit
that referenced
this pull request
Jun 15, 2018
vstinner
added a commit
that referenced
this pull request
Jun 15, 2018
Member
|
@Traceur759: I'm sorry, I had to revert this change because it caused failures on two buildbots: |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This pull request solves problem with reading stack of the interpreter from gdb when new protection flags are used.
The new flags also cause some noise, which is now ignored, on stderr.
https://bugs.python.org/issue32962