* [PATCH] dlm: remove BUG() before panic()
@ 2020-05-07 21:34 ` Arnd Bergmann
0 siblings, 0 replies; 4+ messages in thread
From: Arnd Bergmann @ 2020-05-07 21:34 UTC (permalink / raw)
To: Christine Caulfield, David Teigland, Steve Whitehouse
Cc: Arnd Bergmann, Josh Poimboeuf, clang-built-linux,
Greg Kroah-Hartman, Alexios Zavras, Gustavo A. R. Silva,
Richard Fontana, cluster-devel, linux-kernel
Building a kernel with clang sometimes fails with an objtool error in dlm:
fs/dlm/lock.o: warning: objtool: revert_lock_pc()+0xbd: can't find jump dest instruction at .text+0xd7fc
The problem is that BUG() never returns and the compiler knows
that anything after it is unreachable, however the panic still
emits some code that does not get fully eliminated.
Having both BUG() and panic() is really pointless as the BUG()
kills the current process and the subsequent panic() never hits.
In most cases, we probably don't really want either and should
replace the DLM_ASSERT() statements with WARN_ON(), as has
been done for some of them.
Remove the BUG() here so the user at least sees the panic message
and we can reliably build randconfig kernels.
Fixes: e7fd41792fc0 ("[DLM] The core of the DLM for GFS2/CLVM")
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: clang-built-linux@googlegroups.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/dlm/dlm_internal.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 416d9de35679..4311d01b02a8 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -97,7 +97,6 @@ do { \
__LINE__, __FILE__, #x, jiffies); \
{do} \
printk("\n"); \
- BUG(); \
panic("DLM: Record message above and reboot.\n"); \
} \
}
--
2.26.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [Cluster-devel] [PATCH] dlm: remove BUG() before panic()
@ 2020-05-07 21:34 ` Arnd Bergmann
0 siblings, 0 replies; 4+ messages in thread
From: Arnd Bergmann @ 2020-05-07 21:34 UTC (permalink / raw)
To: cluster-devel.redhat.com
Building a kernel with clang sometimes fails with an objtool error in dlm:
fs/dlm/lock.o: warning: objtool: revert_lock_pc()+0xbd: can't find jump dest instruction at .text+0xd7fc
The problem is that BUG() never returns and the compiler knows
that anything after it is unreachable, however the panic still
emits some code that does not get fully eliminated.
Having both BUG() and panic() is really pointless as the BUG()
kills the current process and the subsequent panic() never hits.
In most cases, we probably don't really want either and should
replace the DLM_ASSERT() statements with WARN_ON(), as has
been done for some of them.
Remove the BUG() here so the user at least sees the panic message
and we can reliably build randconfig kernels.
Fixes: e7fd41792fc0 ("[DLM] The core of the DLM for GFS2/CLVM")
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: clang-built-linux at googlegroups.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/dlm/dlm_internal.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 416d9de35679..4311d01b02a8 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -97,7 +97,6 @@ do { \
__LINE__, __FILE__, #x, jiffies); \
{do} \
printk("\n"); \
- BUG(); \
panic("DLM: Record message above and reboot.\n"); \
} \
}
--
2.26.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] dlm: remove BUG() before panic()
2020-05-07 21:34 ` [Cluster-devel] " Arnd Bergmann
@ 2020-05-08 18:11 ` Nick Desaulniers
-1 siblings, 0 replies; 4+ messages in thread
From: Nick Desaulniers @ 2020-05-08 18:11 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Christine Caulfield, David Teigland, Steve Whitehouse,
Josh Poimboeuf, clang-built-linux, Greg Kroah-Hartman,
Alexios Zavras, Gustavo A. R. Silva, Richard Fontana,
cluster-devel, LKML
On Thu, May 7, 2020 at 2:34 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> Building a kernel with clang sometimes fails with an objtool error in dlm:
>
> fs/dlm/lock.o: warning: objtool: revert_lock_pc()+0xbd: can't find jump dest instruction at .text+0xd7fc
>
> The problem is that BUG() never returns and the compiler knows
> that anything after it is unreachable, however the panic still
> emits some code that does not get fully eliminated.
>
> Having both BUG() and panic() is really pointless as the BUG()
> kills the current process and the subsequent panic() never hits.
> In most cases, we probably don't really want either and should
> replace the DLM_ASSERT() statements with WARN_ON(), as has
> been done for some of them.
>
> Remove the BUG() here so the user at least sees the panic message
> and we can reliably build randconfig kernels.
>
> Fixes: e7fd41792fc0 ("[DLM] The core of the DLM for GFS2/CLVM")
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: clang-built-linux@googlegroups.com
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Thanks for the patch.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> fs/dlm/dlm_internal.h | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
> index 416d9de35679..4311d01b02a8 100644
> --- a/fs/dlm/dlm_internal.h
> +++ b/fs/dlm/dlm_internal.h
> @@ -97,7 +97,6 @@ do { \
> __LINE__, __FILE__, #x, jiffies); \
> {do} \
> printk("\n"); \
> - BUG(); \
> panic("DLM: Record message above and reboot.\n"); \
> } \
> }
> --
> 2.26.0
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 4+ messages in thread* [Cluster-devel] [PATCH] dlm: remove BUG() before panic()
@ 2020-05-08 18:11 ` Nick Desaulniers
0 siblings, 0 replies; 4+ messages in thread
From: Nick Desaulniers @ 2020-05-08 18:11 UTC (permalink / raw)
To: cluster-devel.redhat.com
On Thu, May 7, 2020 at 2:34 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> Building a kernel with clang sometimes fails with an objtool error in dlm:
>
> fs/dlm/lock.o: warning: objtool: revert_lock_pc()+0xbd: can't find jump dest instruction at .text+0xd7fc
>
> The problem is that BUG() never returns and the compiler knows
> that anything after it is unreachable, however the panic still
> emits some code that does not get fully eliminated.
>
> Having both BUG() and panic() is really pointless as the BUG()
> kills the current process and the subsequent panic() never hits.
> In most cases, we probably don't really want either and should
> replace the DLM_ASSERT() statements with WARN_ON(), as has
> been done for some of them.
>
> Remove the BUG() here so the user at least sees the panic message
> and we can reliably build randconfig kernels.
>
> Fixes: e7fd41792fc0 ("[DLM] The core of the DLM for GFS2/CLVM")
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: clang-built-linux at googlegroups.com
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Thanks for the patch.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> fs/dlm/dlm_internal.h | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
> index 416d9de35679..4311d01b02a8 100644
> --- a/fs/dlm/dlm_internal.h
> +++ b/fs/dlm/dlm_internal.h
> @@ -97,7 +97,6 @@ do { \
> __LINE__, __FILE__, #x, jiffies); \
> {do} \
> printk("\n"); \
> - BUG(); \
> panic("DLM: Record message above and reboot.\n"); \
> } \
> }
> --
> 2.26.0
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-05-08 18:11 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-07 21:34 [PATCH] dlm: remove BUG() before panic() Arnd Bergmann
2020-05-07 21:34 ` [Cluster-devel] " Arnd Bergmann
2020-05-08 18:11 ` Nick Desaulniers
2020-05-08 18:11 ` [Cluster-devel] " Nick Desaulniers
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