RFR: 8339331: GCC fortify error in vm_version_linux_aarch64.cpp [v2]

SendaoYan syan at openjdk.org
Tue Dec 10 10:18:13 UTC 2024


> Hi all,
> The file src/hotspot/os_cpu/linux_aarch64/vm_version_linux_aarch64.cpp report nullptr compile warning by gcc14 with fastdebug configure. I think it's false positive, since the statement 'assert(buf != nullptr, "invalid argument");' has make sure the buf should not be nullptr before execute '::read(int, void*, int)'. The call chain is `void VM_Version::initialize_cpu_information(void)` -> `void VM_Version::get_compatible_board(char *buf, int buflen)` -> `static bool read_fully(const char *fname, char *buf, size_t buflen)`, `*buf` is defined as `char  Abstract_VM_Version::_cpu_desc[4096] = {0};` and then right shift 8 bytes, so `*buf` should not be nullptr.
> This PR use suppression pragma macro `PRAGMA_DISABLE_GCC_WARNING("-Wnonnull")` to disable false positive gcc compile warning to make fastdebug configure make success on linux-aarch64 by gcc14.2.0.
> Risk is low.
> 
> Additional testing:
> 
> - [ ]  jtreg tests(include tier1/2/3) on linux-x64 with release build
> - [ ]  jtreg tests(include tier1/2/3) on linux-x64 with fastdebug build
> - [ ]  jtreg tests(include tier1/2/3) on linux-aarch64 with release build
> - [ ]  jtreg tests(include tier1/2/3) on linux-aarch64 with fastdebug build

SendaoYan has updated the pull request incrementally with one additional commit since the last revision:

  Use guarantee instead of assert to suppress gcc warnings

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22655/files
  - new: https://git.openjdk.org/jdk/pull/22655/files/d2296728..110539b0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22655&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22655&range=00-01

  Stats: 4 lines in 1 file changed: 0 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22655.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22655/head:pull/22655

PR: https://git.openjdk.org/jdk/pull/22655


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