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Enable -Wuninitialized #381

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nathanchance opened this issue Feb 26, 2019 · 14 comments
Closed

Enable -Wuninitialized #381

nathanchance opened this issue Feb 26, 2019 · 14 comments
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@nathanchance
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-Wsometimes-uninitialized -Wuninitialized [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] 5.3 This bug was fixed in Linux 5.3

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@nathanchance
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29b00e6 would have been caught with Clang in its default configuration (and not by GCC due to a bug), as pointed out in this thread: https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

However, -Wuninitialized also disables -Wsometimes-uninitialized so this was missed by both compilers :(

I am going to test the following diff then send it along right away if there are no additional warnings:

diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 768306add591..f4332981ea85 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -72,5 +72,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format)
 KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
 KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
+KBUILD_CFLAGS += $(call cc-option, -Wsometimes-uninitialized)
 endif
 endif

Side note, looks like this might be a good time to tell Linus about the KernelCI work that is going on: https://lore.kernel.org/lkml/CAHk-=wggjLsi-1BmDHqWAJPzBvTD_-MQNo5qQ9WCuncnyWPROg@mail.gmail.com/
@nathanchance nathanchance added [BUG] linux A bug that should be fixed in the mainline kernel. [PATCH] Exists There is a patch that fixes this issue labels Feb 26, 2019
@nathanchance nathanchance self-assigned this Feb 26, 2019
@nickdesaulniers
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heh, wish I was cc'ed on that thread (I'm not subbed to lkml, ducks)

@nathanchance
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I'm not subbed to lkml, ducks

Neither am I, I happened to stumble across it while browsing https://lore.kernel.org/lkml/. Guess I should be after this.

It is still possible to reply without being CC'd (if you use mutt). Otherwise, the link gives reply instructions using git send-email at the bottom.

$ curl -LSs -o mbox https://lore.kernel.org/lkml/CAHk-=wggjLsi-1BmDHqWAJPzBvTD_-MQNo5qQ9WCuncnyWPROg@mail.gmail.com/raw
$ mutt -f mbox

@nathanchance nathanchance changed the title -Wno-uninitialized also disabled -Wsometimes-uninitialized Enable -Wsometimes-uninitialized Feb 26, 2019
@nathanchance
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Unfortunately, introduces a few warnings: https://gist.github.com/nathanchance/59f35754366c7d68141a5f44fe9302b8

Another project like #378 (seems like it could be achieved quicker).

@nickdesaulniers
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Yes; and many of those have the same source file (and even the same warning in some cases; like maybe a shared problematic macro). Thanks for the link; I'll file bugs for all of those, and we'll use this to track enabling the warning.

This was referenced Feb 26, 2019
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@nickdesaulniers
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12 altogether (including this one)

This was referenced Feb 26, 2019
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@nathanchance nathanchance added [PATCH] Accepted A submitted patch has been accepted upstream and removed [PATCH] Submitted A patch has been submitted for review labels Jun 24, 2019
masahir0y pushed a commit to masahir0y/linux that referenced this issue Jul 7, 2019
@nathanchance @masahir0y
kbuild: Enable -Wuninitialized
9fc219e 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
masahir0y pushed a commit to masahir0y/linux that referenced this issue Jul 8, 2019
@nathanchance @masahir0y
kbuild: Enable -Wuninitialized
5c052ed 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
masahir0y pushed a commit to masahir0y/linux that referenced this issue Jul 9, 2019
@nathanchance @masahir0y
kbuild: Enable -Wuninitialized
c9199ab 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
masahir0y pushed a commit to masahir0y/linux that referenced this issue Jul 9, 2019
@nathanchance @masahir0y
kbuild: Enable -Wuninitialized
ebe18e1 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
masahir0y pushed a commit to masahir0y/linux that referenced this issue Jul 12, 2019
@nathanchance @masahir0y
kbuild: Enable -Wuninitialized
c036004 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
@nathanchance
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Merged into mainline: https://git.kernel.org/torvalds/c/3a61925e91ba9f0ece1b444eb1aa49caa59e4ae7

@nathanchance nathanchance added [FIXED][LINUX] 5.3 This bug was fixed in Linux 5.3 and removed [PATCH] Accepted A submitted patch has been accepted upstream labels Jul 12, 2019
Eamo5 pushed a commit to Eamo5/linux that referenced this issue Jul 21, 2019
@nathanchance @Eamo5
kbuild: Enable -Wuninitialized
a826101 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Eamo5 pushed a commit to Eamo5/linux that referenced this issue Jul 22, 2019
@nathanchance @Eamo5
kbuild: Enable -Wuninitialized
2f3488b 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Eamon Powell <eamonpowell@outlook.com>
0ranko0P pushed a commit to 0ranko0P/kernel_xiaomi_msm8998 that referenced this issue Oct 27, 2019
@nathanchance
kbuild: Enable -Wuninitialized
10e3a5b 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
0ranko0P pushed a commit to 0ranko0P/kernel_xiaomi_msm8998 that referenced this issue Oct 28, 2019
@nathanchance @0ranko0P
kbuild: Enable -Wuninitialized
15b9528 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Dec 24, 2019
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
369448f 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Dec 25, 2019
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
5029fd4 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Jan 7, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
4271687 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Jan 28, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
c0dbc5e 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
RealAkito pushed a commit to HarukaNetwork/haruka-workstation-kernel that referenced this issue Mar 23, 2020
@nathanchance @RealAkito
Revert "drm/i915: Disable -Wuninitialized"
c070c71 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
Signed-off-by: Akito Mizukito <akito@evolution-x.org>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Apr 2, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
a950e07 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
nathanchance pushed a commit that referenced this issue Jun 11, 2020
@osctobe @tiwai
ALSA: pcm: fix snd_pcm_link() lockdep splat
e18035c 
Add and use snd_pcm_stream_lock_nested() in snd_pcm_link/unlink
implementation.  The code is fine, but generates a lockdep complaint:

============================================
WARNING: possible recursive locking detected
5.7.1mq+ #381 Tainted: G           O
--------------------------------------------
pulseaudio/4180 is trying to acquire lock:
ffff888402d6f508 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xda8/0xee0 [snd_pcm]

but task is already holding lock:
ffff8883f7a8cf18 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xe4e/0xee0 [snd_pcm]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&group->lock);
  lock(&group->lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by pulseaudio/4180:
 #0: ffffffffa1a05190 (snd_pcm_link_rwsem){++++}-{3:3}, at: snd_pcm_common_ioctl+0xca0/0xee0 [snd_pcm]
 #1: ffff8883f7a8cf18 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xe4e/0xee0 [snd_pcm]
[...]

Cc: stable@vger.kernel.org
Fixes: f57f3df ("ALSA: pcm: More fine-grained PCM link locking")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/37252c65941e58473b1219ca9fab03d48f47e3e3.1591610330.git.mirq-linux@rere.qmqm.pl

Signed-off-by: Takashi Iwai <tiwai@suse.de>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Jun 19, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
c27a634 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Jun 22, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
3f47469 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Albert I <kras@raphielgang.org>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Aug 23, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
67f0027 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Aug 24, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
3b2c295 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Aug 24, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
70e1774 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Aug 24, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
4f2ed52 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
krasCGQ pushed a commit to krasCGQ/linux that referenced this issue Aug 24, 2020
@nathanchance @krasCGQ
Revert "drm/i915: Disable -Wuninitialized"
9559d92 
This will be turned on for the whole kernel, as we want to catch these
cases.

This reverts commit c562746.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
0ranko0P pushed a commit to 0ranko0P/kernel_xiaomi_msm8998 that referenced this issue Nov 2, 2020
@nathanchance @0ranko0P
kbuild: Enable -Wuninitialized
604c597 
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: ClangBuiltLinux/linux#381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: 0ranko0P <ranko0p@outlook.com>
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-Wsometimes-uninitialized -Wuninitialized [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] 5.3 This bug was fixed in Linux 5.3
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