72165c867f
Clang prior to 17.0.0 has a bug in its asm goto jump scope analysis to
determine that no variables with the cleanup attribute are skipped by an
indirect jump. Instead of only checking the scope of each label that is
a possible target of each asm goto statement, it checks the scope of
every label, which can cause an error when a variable with the cleanup
attribute is used between two asm goto statements with different scopes,
even if they have completely different label targets:
sound/core/hwdep.c:273:8: error: cannot jump from this asm goto statement to one of its possible targets
if (get_user(device, (int __user *)arg))
^
arch/powerpc/include/asm/uaccess.h:295:5: note: expanded from macro 'get_user'
__get_user(x, _gu_addr) : \
^
arch/powerpc/include/asm/uaccess.h:283:2: note: expanded from macro '__get_user'
__get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \
^
arch/powerpc/include/asm/uaccess.h:199:3: note: expanded from macro '__get_user_size_allowed'
__get_user_size_goto(x, ptr, size, __gus_failed); \
^
arch/powerpc/include/asm/uaccess.h:187:10: note: expanded from macro '__get_user_size_goto'
case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break; \
^
arch/powerpc/include/asm/uaccess.h:158:2: note: expanded from macro '__get_user_asm_goto'
asm_volatile_goto( \
^
include/linux/compiler_types.h:366:33: note: expanded from macro 'asm_volatile_goto'
#define asm_volatile_goto(x...) asm goto(x)
^
sound/core/hwdep.c:291:9: note: possible target of asm goto statement
if (put_user(device, (int __user *)arg))
^
arch/powerpc/include/asm/uaccess.h:66:5: note: expanded from macro 'put_user'
__put_user(x, _pu_addr) : -EFAULT; \
^
arch/powerpc/include/asm/uaccess.h:52:9: note: expanded from macro '__put_user'
\
^
sound/core/hwdep.c:276:4: note: jump bypasses initialization of variable with __attribute__((cleanup))
scoped_guard(mutex, ®ister_mutex) {
^
include/linux/cleanup.h:169:20: note: expanded from macro 'scoped_guard'
for (CLASS(_name, scope)(args), \
To avoid this issue, move the put_user() call out of the scoped_guard()
scope, which allows the asm goto scope analysis to see that the variable
with the cleanup attribute will never be skipped by the asm goto
statements.
There should be no functional change because prior to the refactoring,
put_user() was not called under register_mutex, so this call does not
even need to be in the scoped_guard() in the first place.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.