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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-27 11:04:18 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-27 11:04:18 -0700 |
commit | 88c5083442454e5e8a505b11fa16f32d2879651e (patch) | |
tree | 54774b7dc8cb3bf3d9cb661f63bc40fd5190fa54 /Documentation | |
parent | 43e317c1bbdfe1d4d6d19d28f925f400898d41b9 (diff) | |
parent | a035d552a93bb9ef6048733bb9f2a0dc857ff869 (diff) | |
download | linux-88c5083442454e5e8a505b11fa16f32d2879651e.tar.gz linux-88c5083442454e5e8a505b11fa16f32d2879651e.tar.bz2 linux-88c5083442454e5e8a505b11fa16f32d2879651e.zip |
Merge tag 'Wimplicit-fallthrough-5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux
Pull Wimplicit-fallthrough enablement from Gustavo A. R. Silva:
"This marks switch cases where we are expecting to fall through, and
globally enables the -Wimplicit-fallthrough option in the main
Makefile.
Finally, some missing-break fixes that have been tagged for -stable:
- drm/amdkfd: Fix missing break in switch statement
- drm/amdgpu/gfx10: Fix missing break in switch statement
With these changes, we completely get rid of all the fall-through
warnings in the kernel"
* tag 'Wimplicit-fallthrough-5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
Makefile: Globally enable fall-through warning
drm/i915: Mark expected switch fall-throughs
drm/amd/display: Mark expected switch fall-throughs
drm/amdkfd/kfd_mqd_manager_v10: Avoid fall-through warning
drm/amdgpu/gfx10: Fix missing break in switch statement
drm/amdkfd: Fix missing break in switch statement
perf/x86/intel: Mark expected switch fall-throughs
mtd: onenand_base: Mark expected switch fall-through
afs: fsclient: Mark expected switch fall-throughs
afs: yfsclient: Mark expected switch fall-throughs
can: mark expected switch fall-throughs
firewire: mark expected switch fall-throughs
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/process/deprecated.rst | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst index 49e0f64a3427..053b24a6dd38 100644 --- a/Documentation/process/deprecated.rst +++ b/Documentation/process/deprecated.rst @@ -119,3 +119,17 @@ array may exceed the remaining memory in the stack segment. This could lead to a crash, possible overwriting sensitive contents at the end of the stack (when built without `CONFIG_THREAD_INFO_IN_TASK=y`), or overwriting memory adjacent to the stack (when built without `CONFIG_VMAP_STACK=y`) + +Implicit switch case fall-through +--------------------------------- +The C language allows switch cases to "fall through" when +a "break" statement is missing at the end of a case. This, +however, introduces ambiguity in the code, as it's not always +clear if the missing break is intentional or a bug. As there +have been a long list of flaws `due to missing "break" statements +<https://cwe.mitre.org/data/definitions/484.html>`_, we no longer allow +"implicit fall-through". In order to identify an intentional fall-through +case, we have adopted the marking used by static analyzers: a comment +saying `/* Fall through */`. Once the C++17 `__attribute__((fallthrough))` +is more widely handled by C compilers, static analyzers, and IDEs, we can +switch to using that instead. |