Re: [PATCH 00/33] Compile-time stack metadata validation

On Fri, Jan 22, 2016 at 11:43:48AM -0600, Chris J Arges wrote:

On Thu, Jan 21, 2016 at 04:49:04PM -0600, Josh Poimboeuf wrote:

quoted

This is v16 of the compile-time stack metadata validation patch set,
along with proposed fixes for most of the warnings it found.  It's based
on the tip/master branch.

Josh,

Looks good, with my config [1] I do still get a few warnings building
linux/linux-next.

Here are the warnings:
$ grep ^stacktool build.log | grep -v staging

Thanks for reporting these!

stacktool: arch/x86/kvm/vmx.o: vmx_handle_external_intr()+0x67: call without frame pointer save/setup

This can be fixed by setting the stack pointer as an output operand for
the inline asm call in vmx_handle_external_intr().

Feel free to submit a patch, or I'll get around to it eventually.

stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x9e: return without frame pointer restore
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x89: duplicate frame pointer save
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x8a: duplicate frame pointer setup
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x9e: frame pointer state mismatch
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x0: frame pointer state mismatch

These are false positives.  Stacktool is confused by the use of a
"noreturn" function which it doesn't know about (__reiserfs_panic).

Unfortunately the only solution I currently have for dealing with global
noreturn functions is to just hard-code a list of them.  So the short
term fix would be to add "__reiserfs_panic" to the global_noreturns list
in tools/stacktool/builtin-check.c.

I'm still trying to figure out a better way to deal with this type of
issue, as it's a pain to have to keep a hard-coded list of noreturn
functions.  Unfortunately that info isn't available in the ELF.

stacktool: fs/reiserfs/ibalance.o: .text: unexpected end of section
stacktool: fs/reiserfs/tail_conversion.o: .text: unexpected end of section

For some reason I'm not able to recreate these warnings...  Can you
share one of the .o files?

-- 
Josh
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