| // SPDX-License-Identifier: GPL-2.0-only |
| ///Find conditions where if and else branch are functionally |
| // identical. |
| // |
| // There can be false positives in cases where the positional |
| // information is used (as with lockdep) or where the identity |
| // is a placeholder for not yet handled cases. |
| // Unfortunately there also seems to be a tendency to use |
| // the last if else/else as a "default behavior" - which some |
| // might consider a legitimate coding pattern. From discussion |
| // on kernelnewbies though it seems that this is not really an |
| // accepted pattern and if at all it would need to be commented |
| // |
| // In the Linux kernel it does not seem to actually report |
| // false positives except for those that were documented as |
| // being intentional. |
| // the two known cases are: |
| // arch/sh/kernel/traps_64.c:read_opcode() |
| // } else if ((pc & 1) == 0) { |
| // /* SHcompact */ |
| // /* TODO : provide handling for this. We don't really support |
| // user-mode SHcompact yet, and for a kernel fault, this would |
| // have to come from a module built for SHcompact. */ |
| // return -EFAULT; |
| // } else { |
| // /* misaligned */ |
| // return -EFAULT; |
| // } |
| // fs/kernfs/file.c:kernfs_fop_open() |
| // * Both paths of the branch look the same. They're supposed to |
| // * look that way and give @of->mutex different static lockdep keys. |
| // */ |
| // if (has_mmap) |
| // mutex_init(&of->mutex); |
| // else |
| // mutex_init(&of->mutex); |
| // |
| // All other cases look like bugs or at least lack of documentation |
| // |
| // Confidence: Moderate |
| // Copyright: (C) 2016 Nicholas Mc Guire, OSADL. |
| // Comments: |
| // Options: --no-includes --include-headers |
| |
| virtual org |
| virtual report |
| |
| @cond@ |
| statement S1; |
| position p; |
| @@ |
| |
| * if@p (...) S1 else S1 |
| |
| @script:python depends on org@ |
| p << cond.p; |
| @@ |
| |
| cocci.print_main("WARNING: possible condition with no effect (if == else)",p) |
| |
| @script:python depends on report@ |
| p << cond.p; |
| @@ |
| |
| coccilib.report.print_report(p[0],"WARNING: possible condition with no effect (if == else)") |
