[Bug other/85778] unexpected results with -O2, wrong code?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85778 Martin Sebor changed: What|Removed |Added CC||msebor at gcc dot gnu.org --- Comment #5 from Martin Sebor --- (In reply to Scott Emmons from comment #4) > > glibc has stat annotated with nonnull(1, 2) > > 1. Can you provide a reference to this code? This is helpful so that other > people running into this (and it *will* happen, this ancient code no longer > runs correctly). Thank you. stat() is a POSIX function and (similarly to C) POSIX specifies (in 2.1.1 Use and Implementation of Functions of XSH) that: If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer), the behavior is undefined. A link to the section in the latest spec: pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_01_01
[Bug other/85778] unexpected results with -O2, wrong code?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85778 --- Comment #4 from Scott Emmons --- > glibc has stat annotated with nonnull(1, 2) 1. Can you provide a reference to this code? This is helpful so that other people running into this (and it *will* happen, this ancient code no longer runs correctly). Thank you. 2. The manpage for stat(2) should be updated to reflect that calling stat() with a NULL pathname will result in unpredictable behavior. 3. I'll create a pull request against cronolog and work with Debian/Ubuntu to at least get it fixed in those distributions.
[Bug other/85778] unexpected results with -O2, wrong code?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85778 Richard Biener changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Version|unknown |8.1.0 Resolution|--- |INVALID --- Comment #3 from Richard Biener --- glibc has stat annotated with nonnull(1, 2)
[Bug other/85778] unexpected results with -O2, wrong code?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85778 Scott E. changed: What|Removed |Added CC||sesail999 at gmail dot com --- Comment #2 from Scott E. --- Just to add a few more details, I discovered this via "cronolog", which does this pattern of stat() with a null pathname. Not that it makes the code correct, and it could easily be guarded against, however this code has been working fine since 2001 [1]. There's a few more details in the downstream bug report [2]. [1] https://github.com/fordmason/cronolog/blame/83f9e99d6bd5cb8f5cc06723f4d79d1265582340/src/cronoutils.c#L250 [2] https://bugs.launchpad.net/ubuntu/+source/gcc-5/+bug/1770676
[Bug other/85778] unexpected results with -O2, wrong code?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85778 --- Comment #1 from Andrew Pinski --- It depends on if glibc is adding the nonnull attribute to stat or is it GCC. Also what does the C (and POSIX) standard says about a null pointer being passed as the string to stat.
