///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. GPLv2. // 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)")
Name | Type | Size | Permission | Actions |
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array_size.cocci | File | 1.66 KB | 0644 |
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badty.cocci | File | 1.68 KB | 0644 |
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boolconv.cocci | File | 1.44 KB | 0644 |
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boolinit.cocci | File | 2.2 KB | 0644 |
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boolreturn.cocci | File | 698 B | 0644 |
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bugon.cocci | File | 1.45 KB | 0644 |
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cond_no_effect.cocci | File | 2.04 KB | 0644 |
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cstptr.cocci | File | 827 B | 0644 |
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doubleinit.cocci | File | 1.36 KB | 0644 |
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ifaddr.cocci | File | 659 B | 0644 |
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ifcol.cocci | File | 1.21 KB | 0644 |
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irqf_oneshot.cocci | File | 1.91 KB | 0644 |
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noderef.cocci | File | 1.17 KB | 0644 |
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of_table.cocci | File | 1.33 KB | 0644 |
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orplus.cocci | File | 1 KB | 0644 |
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returnvar.cocci | File | 1.22 KB | 0644 |
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semicolon.cocci | File | 1.04 KB | 0644 |
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warn.cocci | File | 1.62 KB | 0644 |
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