- 05 6月, 2020 1 次提交
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由 Will Deacon 提交于
READ_ONCE() permits 64-bit accesses on 32-bit architectures, since this crops up in a few places and is generally harmless because either the upper bits are always zero (e.g. for a virtual address or 32-bit time_t) or the architecture provides 64-bit atomicity anyway. Update the corresponding comment above compiletime_assert_rwonce_type(), which incorrectly states that 32-bit x86 provides 64-bit atomicity, and instead reference 32-bit Armv7 with LPAE. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Reported-by: NJann Horn <jannh@google.com> Signed-off-by: NWill Deacon <will@kernel.org>
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- 16 4月, 2020 3 次提交
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由 Will Deacon 提交于
Passing a volatile-qualified pointer to READ_ONCE() is an absolute trainwreck for code generation: the use of 'typeof()' to define a temporary variable inside the macro means that the final evaluation in macro scope ends up forcing a read back from the stack. When stack protector is enabled (the default for arm64, at least), this causes the compiler to vomit up all sorts of junk. Unfortunately, dropping pointer qualifiers inside the macro poses quite a challenge, especially since the pointed-to type is permitted to be an aggregate, and this is relied upon by mm/ code accessing things like 'pmd_t'. Based on numerous hacks and discussions on the mailing list, this is the best I've managed to come up with. Introduce '__unqual_scalar_typeof()' which takes an expression and, if the expression is an optionally qualified 8, 16, 32 or 64-bit scalar type, evaluates to the unqualified type. Other input types, including aggregates, remain unchanged. Hopefully READ_ONCE() on volatile aggregate pointers isn't something we do on a fast-path. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org> Reported-by: NMichael Ellerman <mpe@ellerman.id.au> Signed-off-by: NWill Deacon <will@kernel.org>
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由 Will Deacon 提交于
{READ,WRITE}_ONCE() cannot guarantee atomicity for arbitrary data sizes. This can be surprising to callers that might incorrectly be expecting atomicity for accesses to aggregate structures, although there are other callers where tearing is actually permissable (e.g. if they are using something akin to sequence locking to protect the access). Linus sayeth: | We could also look at being stricter for the normal READ/WRITE_ONCE(), | and require that they are | | (a) regular integer types | | (b) fit in an atomic word | | We actually did (b) for a while, until we noticed that we do it on | loff_t's etc and relaxed the rules. But maybe we could have a | "non-atomic" version of READ/WRITE_ONCE() that is used for the | questionable cases? The slight snag is that we also have to support 64-bit accesses on 32-bit architectures, as these appear to be widespread and tend to work out ok if either the architecture supports atomic 64-bit accesses (x86, armv7) or if the variable being accesses represents a virtual address and therefore only requires 32-bit atomicity in practice. Take a step in that direction by introducing a variant of 'compiletime_assert_atomic_type()' and use it to check the pointer argument to {READ,WRITE}_ONCE(). Expose __{READ,WRITE}_ONCE() variants which are allowed to tear and convert the one broken caller over to the new macros. Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: NWill Deacon <will@kernel.org>
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由 Will Deacon 提交于
The implementations of {READ,WRITE}_ONCE() suffer from a significant amount of indirection and complexity due to a historic GCC bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 which was originally worked around by 230fa253 ("kernel: Provide READ_ONCE and ASSIGN_ONCE"). Since GCC 4.8 is fairly vintage at this point and we emit a warning if we detect it during the build, return {READ,WRITE}_ONCE() to their former glory with an implementation that is easier to understand and, crucially, more amenable to optimisation. A side effect of this simplification is that WRITE_ONCE() no longer returns a value, but nobody seems to be relying on that and the new behaviour is aligned with smp_store_release(). Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NWill Deacon <will@kernel.org>
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- 08 4月, 2020 1 次提交
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由 Vegard Nossum 提交于
compiletime_assert() uses __LINE__ to create a unique function name. This means that if you have more than one BUILD_BUG_ON() in the same source line (which can happen if they appear e.g. in a macro), then the error message from the compiler might output the wrong condition. For this source file: #include <linux/build_bug.h> #define macro() \ BUILD_BUG_ON(1); \ BUILD_BUG_ON(0); void foo() { macro(); } gcc would output: ./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_9' declared with attribute error: BUILD_BUG_ON failed: 0 _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) However, it was not the BUILD_BUG_ON(0) that failed, so it should say 1 instead of 0. With this patch, we use __COUNTER__ instead of __LINE__, so each BUILD_BUG_ON() gets a different function name and the correct condition is printed: ./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_0' declared with attribute error: BUILD_BUG_ON failed: 1 _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NMasahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: NDaniel Santos <daniel.santos@pobox.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Ian Abbott <abbotti@mev.co.uk> Cc: Joe Perches <joe@perches.com> Link: http://lkml.kernel.org/r/20200331112637.25047-1-vegard.nossum@oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 9月, 2019 1 次提交
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由 Nick Desaulniers 提交于
GCC unescapes escaped string section names while Clang does not. Because __section uses the `#` stringification operator for the section name, it doesn't need to be escaped. This fixes an Oops observed in distro's that use systemd and not net.core.bpf_jit_enable=1, when their kernels are compiled with Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/619 Link: https://bugs.llvm.org/show_bug.cgi?id=42950 Link: https://marc.info/?l=linux-netdev&m=156412960619946&w=2 Link: https://lore.kernel.org/lkml/20190904181740.GA19688@gmail.com/Acked-by: NWill Deacon <will@kernel.org> Reported-by: NSedat Dilek <sedat.dilek@gmail.com> Suggested-by: NJosh Poimboeuf <jpoimboe@redhat.com> Tested-by: NSedat Dilek <sedat.dilek@gmail.com> Signed-off-by: NNick Desaulniers <ndesaulniers@google.com> [Cherry-picked from the __section cleanup series for 5.3] [Adjusted commit message] Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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- 09 7月, 2019 1 次提交
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由 Josh Poimboeuf 提交于
Objtool doesn't know how to read C jump tables, so it has to whitelist functions which use them, causing missing ORC unwinder data for such functions, e.g. ___bpf_prog_run(). C jump tables are very similar to GCC switch jump tables, which objtool already knows how to read. So adding support for C jump tables is easy. It just needs to be able to find the tables and distinguish them from other data. To allow the jump tables to be found, create an __annotate_jump_table macro which can be used to annotate them. The annotation is done by placing the jump table in an .rodata..c_jump_table section. The '.rodata' prefix ensures that the data will be placed in the rodata section by the vmlinux linker script. The double periods are part of an existing convention which distinguishes kernel sections from GCC sections. Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <songliubraving@fb.com> Cc: Kairui Song <kasong@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Link: https://lkml.kernel.org/r/0ba2ca30442b16b97165992381ce643dc27b3d1a.1561685471.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 10 5月, 2019 1 次提交
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由 Linus Torvalds 提交于
Peter Zijlstra noticed that with CONFIG_PROFILE_ALL_BRANCHES, the "if" macro converts the conditional to an array index. This can cause GCC to create horrible code. When there are nested ifs, the generated code uses register values to encode branching decisions. Josh Poimboeuf found that replacing the define "if" macro from using the condition as an array index and incrementing the branch statics with an if statement itself, reduced the asm complexity and shrinks the generated code quite a bit. But this can be simplified even further by replacing the internal if statement with a ternary operator. Link: https://lkml.kernel.org/r/20190307174802.46fmpysxyo35hh43@treble Link: http://lkml.kernel.org/r/CAHk-=wiALN3jRuzARpwThN62iKd476Xj-uom+YnLZ4=eqcz7xQ@mail.gmail.comReported-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Reported-by: NJosh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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- 03 4月, 2019 1 次提交
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由 Josh Poimboeuf 提交于
With CONFIG_PROFILE_ALL_BRANCHES=y, the "if" macro converts the conditional to an array index. This can cause GCC to create horrible code. When there are nested ifs, the generated code uses register values to encode branching decisions. Make it easier for GCC to optimize by keeping the conditional as a conditional rather than converting it to an integer. This shrinks the generated code quite a bit, and also makes the code sane enough for objtool to understand. Reported-by: NPeter Zijlstra <peterz@infradead.org> Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: brgerst@gmail.com Cc: catalin.marinas@arm.com Cc: dvlasenk@redhat.com Cc: dvyukov@google.com Cc: hpa@zytor.com Cc: james.morse@arm.com Cc: julien.thierry@arm.com Cc: luto@amacapital.net Cc: luto@kernel.org Cc: rostedt@goodmis.org Cc: valentin.schneider@arm.com Cc: will.deacon@arm.com Link: https://lkml.kernel.org/r/20190307174802.46fmpysxyo35hh43@trebleSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 09 1月, 2019 1 次提交
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由 Michael S. Tsirkin 提交于
Since commit 815f0ddb ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") clang no longer reuses the OPTIMIZER_HIDE_VAR macro from compiler-gcc - instead it gets the version in include/linux/compiler.h. Unfortunately that version doesn't actually prevent compiler from optimizing out the variable. Fix up by moving the macro out from compiler-gcc.h to compiler.h. Compilers without incline asm support will keep working since it's protected by an ifdef. Also fix up comments to match reality since we are no longer overriding any macros. Build-tested with gcc and clang. Fixes: 815f0ddb ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") Cc: Eli Friedman <efriedma@codeaurora.org> Cc: Joe Perches <joe@perches.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Signed-off-by: NMichael S. Tsirkin <mst@redhat.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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- 19 12月, 2018 1 次提交
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由 Ingo Molnar 提交于
This reverts commit c06c4d80. See this commit for details about the revert: e769742d ("Revert "x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs"") Reported-by: NMasahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: NBorislav Petkov <bp@alien8.de> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: Juergen Gross <jgross@suse.com> Cc: Richard Biener <rguenther@suse.de> Cc: Kees Cook <keescook@chromium.org> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Nadav Amit <namit@vmware.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 06 11月, 2018 1 次提交
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由 Martin Schwidefsky 提交于
The __no_sanitize_address_or_inline and __no_kasan_or_inline defines are almost identical. The only difference is that __no_kasan_or_inline does not have the 'notrace' attribute. To be able to replace __no_sanitize_address_or_inline with the older definition, add 'notrace' to __no_kasan_or_inline and change to two users of __no_sanitize_address_or_inline in the s390 code. The 'notrace' option is necessary for e.g. the __load_psw_mask function in arch/s390/include/asm/processor.h. Without the option it is possible to trace __load_psw_mask which leads to kernel stack overflow. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Pointed-out-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: NSteven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 19 10月, 2018 1 次提交
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由 ndesaulniers@google.com 提交于
Fixes the objtool warning seen with Clang: arch/x86/mm/fault.o: warning: objtool: no_context()+0x220: unreachable instruction Fixes commit 815f0ddb ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") Josh noted that the fallback definition was meant to work around a pre-gcc-4.6 bug. GCC still needs to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365, so compiler-gcc.h defines its own version of unreachable(). Clang and ICC can use this shared definition. Link: https://github.com/ClangBuiltLinux/linux/issues/204Suggested-by: NAndy Lutomirski <luto@amacapital.net> Suggested-by: NJosh Poimboeuf <jpoimboe@redhat.com> Tested-by: NNathan Chancellor <natechancellor@gmail.com> Signed-off-by: NNick Desaulniers <ndesaulniers@google.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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- 11 10月, 2018 1 次提交
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由 Masahiro Yamada 提交于
__compiletime_assert_fallback() is supposed to stop building earlier by using the negative-array-size method in case the compiler does not support "error" attribute, but has never worked like that. You can simply try: BUILD_BUG_ON(1); GCC immediately terminates the build, but Clang does not report anything because Clang does not support the "error" attribute now. It will later fail at link time, but __compiletime_assert_fallback() is not working at least. The root cause is commit 1d6a0d19 ("bug.h: prevent double evaluation of `condition' in BUILD_BUG_ON"). Prior to that commit, BUILD_BUG_ON() was checked by the negative-array-size method *and* the link-time trick. Since that commit, the negative-array-size is not effective because '__cond' is no longer constant. As the comment in <linux/build_bug.h> says, GCC (and Clang as well) only emits the error for obvious cases. When '__cond' is a variable, ((void)sizeof(char[1 - 2 * __cond])) ... is not obvious for the compiler to know the array size is negative. Reverting that commit would break BUILD_BUG() because negative-size-array is evaluated before the code is optimized out. Let's give up __compiletime_assert_fallback(). This commit does not change the current behavior since it just rips off the useless code. Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: NKees Cook <keescook@chromium.org> Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Signed-off-by: NKees Cook <keescook@chromium.org>
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- 04 10月, 2018 1 次提交
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由 Nadav Amit 提交于
As described in: 77b0bf55: ("kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs") GCC's inlining heuristics are broken with common asm() patterns used in kernel code, resulting in the effective disabling of inlining. In the case of objtool the resulting borkage can be significant, since all the annotations of objtool are discarded during linkage and never inlined, yet GCC bogusly considers most functions affected by objtool annotations as 'too large'. The workaround is to set an assembly macro and call it from the inline assembly block. As a result GCC considers the inline assembly block as a single instruction. (Which it isn't, but that's the best we can get.) This increases the kernel size slightly: text data bss dec hex filename 18140829 10224724 2957312 31322865 1ddf2f1 ./vmlinux before 18140970 10225412 2957312 31323694 1ddf62e ./vmlinux after (+829) The number of static text symbols (i.e. non-inlined functions) is reduced: Before: 40321 After: 40302 (-19) [ mingo: Rewrote the changelog. ] Tested-by: NKees Cook <keescook@chromium.org> Signed-off-by: NNadav Amit <namit@vmware.com> Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com> Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Christopher Li <sparse@chrisli.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-sparse@vger.kernel.org Link: http://lkml.kernel.org/r/20181003213100.189959-4-namit@vmware.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 01 10月, 2018 6 次提交
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由 Miguel Ojeda 提交于
Suggested-by: NNick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7 Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Reviewed-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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由 Miguel Ojeda 提交于
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7 Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Reviewed-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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由 Miguel Ojeda 提交于
Sparse knows about a few more attributes now, so we can remove the __CHECKER__ conditions from them (which, in turn, allow us to move some of them later on to compiler_attributes.h). * assume_aligned: since sparse's commit ffc860b ("sparse: ignore __assume_aligned__ attribute"), included in 0.5.1 * error: since sparse's commit 0a04210 ("sparse: Add 'error' to ignored attributes"), included in 0.5.0 * hotpatch: since sparse's commit 6043210 ("sparse/parse.c: ignore hotpatch attribute"), included in 0.5.1 * warning: since sparse's commit 977365d ("Avoid "attribute 'warning': unknown attribute" warning"), included in 0.4.2 On top of that, __must_be_array does not need it either because: * Even ancient versions of sparse do not have a problem * BUILD_BUG_ON_ZERO() is currently disabled for __CHECKER__ Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7 Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Reviewed-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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由 Miguel Ojeda 提交于
Different definitions of __must_be_array: * gcc: disabled for __CHECKER__ * clang: same definition as gcc's, but without __CHECKER__ * intel: the comment claims __builtin_types_compatible_p() is unsupported; but icc seems to support it since 13.0.1 (released in 2012). See https://godbolt.org/z/S0l6QQ Therefore, we can remove all of them and have a single definition in compiler.h Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7 Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Reviewed-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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由 Miguel Ojeda 提交于
The attribute syntax optionally allows to surround attribute names with "__" in order to avoid collisions with macros of the same name (see https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html). This homogenizes all attributes to use the syntax with underscores. While there are currently only a handful of cases of some TUs defining macros like "error" which may collide with the attributes, this should prevent futures surprises. This has been done only for "standard" attributes supported by the major compilers. In other words, those of third-party tools (e.g. sparse, plugins...) have not been changed for the moment. Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7 Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Reviewed-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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由 Miguel Ojeda 提交于
__optimize and __deprecate_for_modules are unused in the whole kernel tree. Simply drop them. Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7 Reviewed-by: NNick Desaulniers <ndesaulniers@google.com> Reviewed-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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- 23 8月, 2018 2 次提交
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由 Ard Biesheuvel 提交于
An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab entries, each consisting of two 64-bit fields containing absolute references, to the symbol itself and to a char array containing its name, respectively. When we build the same configuration with KASLR enabled, we end up with an additional ~192 KB of relocations in the .init section, i.e., one 24 byte entry for each absolute reference, which all need to be processed at boot time. Given how the struct kernel_symbol that describes each entry is completely local to module.c (except for the references emitted by EXPORT_SYMBOL() itself), we can easily modify it to contain two 32-bit relative references instead. This reduces the size of the __ksymtab section by 50% for all 64-bit architectures, and gets rid of the runtime relocations entirely for architectures implementing KASLR, either via standard PIE linking (arm64) or using custom host tools (x86). Note that the binary search involving __ksymtab contents relies on each section being sorted by symbol name. This is implemented based on the input section names, not the names in the ksymtab entries, so this patch does not interfere with that. Given that the use of place-relative relocations requires support both in the toolchain and in the module loader, we cannot enable this feature for all architectures. So make it dependent on whether CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined. Link: http://lkml.kernel.org/r/20180704083651.24360-4-ard.biesheuvel@linaro.orgSigned-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: NJessica Yu <jeyu@kernel.org> Acked-by: NMichael Ellerman <mpe@ellerman.id.au> Reviewed-by: NWill Deacon <will.deacon@arm.com> Acked-by: NIngo Molnar <mingo@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morris <james.morris@microsoft.com> Cc: James Morris <jmorris@namei.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Russell King <linux@armlinux.org.uk> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Rasmus Villemoes 提交于
Appararently, it's possible to have a non-trivial TU include a few headers, including linux/build_bug.h, without ending up with linux/types.h. So the 0day bot sent me config: um-x86_64_defconfig (attached as .config) >> include/linux/compiler.h:316:3: error: unknown type name 'bool'; did you mean '_Bool'? bool __cond = !(condition); \ for something I'm working on. Rather than contributing to the #include madness and including linux/types.h from compiler.h, just use int. Link: http://lkml.kernel.org/r/20180817101036.20969-1-linux@rasmusvillemoes.dkSigned-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Christopher Li <sparse@chrisli.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 6月, 2018 1 次提交
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由 Mikulas Patocka 提交于
The function __builtin_expect returns long type (see the gcc documentation), and so do macros likely and unlikely. Unfortunatelly, when CONFIG_PROFILE_ANNOTATED_BRANCHES is selected, the macros likely and unlikely expand to __branch_check__ and __branch_check__ truncates the long type to int. This unintended truncation may cause bugs in various kernel code (we found a bug in dm-writecache because of it), so it's better to fix __branch_check__ to return long. Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1805300818140.24812@file01.intranet.prod.int.rdu2.redhat.com Cc: Ingo Molnar <mingo@redhat.com> Cc: stable@vger.kernel.org Fixes: 1f0d69a9 ("tracing: profile likely and unlikely annotations") Signed-off-by: NMikulas Patocka <mpatocka@redhat.com> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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- 22 2月, 2018 1 次提交
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由 Arnd Bergmann 提交于
Looking at functions with large stack frames across all architectures led me discovering that BUG() suffers from the same problem as fortify_panic(), which I've added a workaround for already. In short, variables that go out of scope by calling a noreturn function or __builtin_unreachable() keep using stack space in functions afterwards. A workaround that was identified is to insert an empty assembler statement just before calling the function that doesn't return. I'm adding a macro "barrier_before_unreachable()" to document this, and insert calls to that in all instances of BUG() that currently suffer from this problem. The files that saw the largest change from this had these frame sizes before, and much less with my patch: fs/ext4/inode.c:82:1: warning: the frame size of 1672 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/ext4/namei.c:434:1: warning: the frame size of 904 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/ext4/super.c:2279:1: warning: the frame size of 1160 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/ext4/xattr.c:146:1: warning: the frame size of 1168 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/f2fs/inode.c:152:1: warning: the frame size of 1424 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_core.c:1195:1: warning: the frame size of 1068 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_core.c:395:1: warning: the frame size of 1084 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_ftp.c:298:1: warning: the frame size of 928 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_ftp.c:418:1: warning: the frame size of 908 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_lblcr.c:718:1: warning: the frame size of 960 bytes is larger than 800 bytes [-Wframe-larger-than=] drivers/net/xen-netback/netback.c:1500:1: warning: the frame size of 1088 bytes is larger than 800 bytes [-Wframe-larger-than=] In case of ARC and CRIS, it turns out that the BUG() implementation actually does return (or at least the compiler thinks it does), resulting in lots of warnings about uninitialized variable use and leaving noreturn functions, such as: block/cfq-iosched.c: In function 'cfq_async_queue_prio': block/cfq-iosched.c:3804:1: error: control reaches end of non-void function [-Werror=return-type] include/linux/dmaengine.h: In function 'dma_maxpq': include/linux/dmaengine.h:1123:1: error: control reaches end of non-void function [-Werror=return-type] This makes them call __builtin_trap() instead, which should normally dump the stack and kill the current process, like some of the other architectures already do. I tried adding barrier_before_unreachable() to panic() and fortify_panic() as well, but that had very little effect, so I'm not submitting that patch. Vineet said: : For ARC, it is double win. : : 1. Fixes 3 -Wreturn-type warnings : : | ../net/core/ethtool.c:311:1: warning: control reaches end of non-void function : [-Wreturn-type] : | ../kernel/sched/core.c:3246:1: warning: control reaches end of non-void function : [-Wreturn-type] : | ../include/linux/sunrpc/svc_xprt.h:180:1: warning: control reaches end of : non-void function [-Wreturn-type] : : 2. bloat-o-meter reports code size improvements as gcc elides the : generated code for stack return. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 Link: http://lkml.kernel.org/r/20171219114112.939391-1-arnd@arndb.deSigned-off-by: NArnd Bergmann <arnd@arndb.de> Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc] Tested-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc] Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Christopher Li <sparse@chrisli.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 2月, 2018 1 次提交
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由 Geert Uytterhoeven 提交于
Create a new function attribute __optimize, which allows to specify an optimization level on a per-function basis. Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org> Acked-by: NArd Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
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- 02 2月, 2018 2 次提交
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由 Andrey Ryabinin 提交于
Sometimes we know that it's safe to do potentially out-of-bounds access because we know it won't cross a page boundary. Still, KASAN will report this as a bug. Add read_word_at_a_time() function which is supposed to be used in such cases. In read_word_at_a_time() KASAN performs relaxed check - only the first byte of access is validated. Signed-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrey Ryabinin 提交于
Instead of having two identical __read_once_size_nocheck() functions with different attributes, consolidate all the difference in new macro __no_kasan_or_inline and use it. No functional changes. Signed-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 12月, 2017 1 次提交
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由 Will Deacon 提交于
[ Note, this is a Git cherry-pick of the following commit: 76ebbe78 ("locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()") ... for easier x86 PTI code testing and back-porting. ] In preparation for the removal of lockless_dereference(), which is the same as READ_ONCE() on all architectures other than Alpha, add an implicit smp_read_barrier_depends() to READ_ONCE() so that it can be used to head dependency chains on all architectures. Signed-off-by: NWill Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-3-git-send-email-will.deacon@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 12 12月, 2017 1 次提交
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由 Mark Rutland 提交于
There are no longer any kernelspace uses of ACCESS_ONCE(), so we can remove the definition from <linux/compiler.h>. This patch removes the ACCESS_ONCE() definition, and updates comments which referred to it. At the same time, some inconsistent and redundant whitespace is removed from comments. Tested-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NMark Rutland <mark.rutland@arm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: apw@canonical.com Link: http://lkml.kernel.org/r/20171127103824.36526-4-mark.rutland@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 07 11月, 2017 2 次提交
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由 Josh Poimboeuf 提交于
Add 'volatile' to the unreachable annotation macro inline asm statements. They're already implicitly volatile because they don't have output constraints, but it's clearer and more robust to make them explicitly volatile. Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/28659257b7a6adf4a7f65920dad70b2b0226e996.1509974104.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Josh Poimboeuf 提交于
Add a comment for the unreachable annotation macros to explain their purpose and the '__COUNTER__' label hack. Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1570e48d9f87e0fc6f0126c32e7e1de6e109cb67.1509974104.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 04 11月, 2017 1 次提交
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由 Josh Poimboeuf 提交于
This fixes the following warning with GCC 4.6: mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction The problem is that the compiler merged identical annotate_unreachable() inline asm blocks, resulting in a missing 'unreachable' annotation. This problem happened before, and was partially fixed with: 3d1e2360 ("objtool: Prevent GCC from merging annotate_unreachable()") That commit tried to ensure that each instance of the annotate_unreachable() inline asm statement has a unique label. It used the __LINE__ macro to generate the label number. However, even the line number isn't necessarily unique when used in an inline function with multiple callers (in this case, __alloc_pages_node()'s use of VM_BUG_ON). Reported-by: Nkbuild test robot <fengguang.wu@intel.com> Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kbuild-all@01.org Cc: tipbuild@zytor.com Fixes: 3d1e2360 ("objtool: Prevent GCC from merging annotate_unreachable()") Link: http://lkml.kernel.org/r/20171103221941.cajpwszir7ujxyc4@trebleSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 02 11月, 2017 1 次提交
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由 Greg Kroah-Hartman 提交于
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org> Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 24 10月, 2017 3 次提交
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由 Will Deacon 提交于
lockless_dereference() is a nice idea, but it gained little traction in kernel code since its introduction three years ago. This is partly because it's a pain to type, but also because using READ_ONCE() instead has worked correctly on all architectures apart from Alpha, which is a fully supported but somewhat niche architecture these days. Now that READ_ONCE() has been upgraded to contain an implicit smp_read_barrier_depends() and the few callers of lockless_dereference() have been converted, we can remove lockless_dereference() altogether. Signed-off-by: NWill Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-5-git-send-email-will.deacon@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Will Deacon 提交于
In preparation for the removal of lockless_dereference(), which is the same as READ_ONCE() on all architectures other than Alpha, add an implicit smp_read_barrier_depends() to READ_ONCE() so that it can be used to head dependency chains on all architectures. Signed-off-by: NWill Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-3-git-send-email-will.deacon@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Will Deacon 提交于
linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: NWill Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 01 9月, 2017 1 次提交
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由 Joe Stringer 提交于
Commit c7acec71 ("kernel.h: handle pointers to arrays better in container_of()") made use of __compiletime_assert() from container_of() thus increasing the usage of this macro, allowing developers to notice type conflicts in usage of container_of() at compile time. However, the implementation of __compiletime_assert relies on compiler optimizations to report an error. This means that if a developer uses "-O0" with any code that performs container_of(), the compiler will always report an error regardless of whether there is an actual problem in the code. This patch disables compile_time_assert when optimizations are disabled to allow such code to compile with CFLAGS="-O0". Example compilation failure: ./include/linux/compiler.h:547:38: error: call to `__compiletime_assert_94' declared with attribute error: pointer type mismatch in container_of() _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) ^ ./include/linux/compiler.h:530:4: note: in definition of macro `__compiletime_assert' prefix ## suffix(); \ ^~~~~~ ./include/linux/compiler.h:547:2: note: in expansion of macro `_compiletime_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) ^~~~~~~~~~~~~~~~~~~ ./include/linux/build_bug.h:46:37: note: in expansion of macro `compiletime_assert' #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) ^~~~~~~~~~~~~~~~~~ ./include/linux/kernel.h:860:2: note: in expansion of macro `BUILD_BUG_ON_MSG' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^~~~~~~~~~~~~~~~ [akpm@linux-foundation.org: use do{}while(0), per Michal] Link: http://lkml.kernel.org/r/20170829230114.11662-1-joe@ovn.org Fixes: c7acec71 ("kernel.h: handle pointers to arrays better in container_of()") Signed-off-by: NJoe Stringer <joe@ovn.org> Cc: Ian Abbott <abbotti@mev.co.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 7月, 2017 1 次提交
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由 Josh Poimboeuf 提交于
Arnd reported some false positive warnings with GCC 7: drivers/hid/wacom_wac.o: warning: objtool: wacom_bpt3_touch()+0x2a5: stack state mismatch: cfa1=7+8 cfa2=6+16 drivers/iio/adc/vf610_adc.o: warning: objtool: vf610_adc_calculate_rates() falls through to next function vf610_adc_sample_set() drivers/pwm/pwm-hibvt.o: warning: objtool: hibvt_pwm_get_state() falls through to next function hibvt_pwm_remove() drivers/pwm/pwm-mediatek.o: warning: objtool: mtk_pwm_config() falls through to next function mtk_pwm_enable() drivers/spi/spi-bcm2835.o: warning: objtool: .text: unexpected end of section drivers/spi/spi-bcm2835aux.o: warning: objtool: .text: unexpected end of section drivers/watchdog/digicolor_wdt.o: warning: objtool: dc_wdt_get_timeleft() falls through to next function dc_wdt_restart() When GCC 7 detects a potential divide-by-zero condition, it sometimes inserts a UD2 instruction for the case where the divisor is zero, instead of letting the hardware trap on the divide instruction. Objtool doesn't consider UD2 to be fatal unless it's annotated with unreachable(). So it considers the GCC-generated UD2 to be non-fatal, and it tries to follow the control flow past the UD2 and gets confused. Previously, objtool *did* assume UD2 was always a dead end. That changed with the following commit: d1091c7f ("objtool: Improve detection of BUG() and other dead ends") The motivation behind that change was that Peter was planning on using UD2 for __WARN(), which is *not* a dead end. However, it turns out that some emulators rely on UD2 being fatal, so he ended up using 'ud0' instead: 9a93848f ("x86/debug: Implement __WARN() using UD0") For GCC 4.5+, it should be safe to go back to the previous assumption that UD2 is fatal, even when it's not annotated with unreachable(). But for pre-4.5 versions of GCC, the unreachable() macro isn't supported, so such cases of UD2 need to be explicitly annotated as reachable. Reported-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: d1091c7f ("objtool: Improve detection of BUG() and other dead ends") Link: http://lkml.kernel.org/r/e57fa9dfede25f79487da8126ee9cdf7b856db65.1501188854.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 25 7月, 2017 1 次提交
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由 Kees Cook 提交于
This creates an unreachable annotation in asm for CONFIG_STACK_VALIDATION=y. While here, adjust earlier uses of \t\n into \n\t. Suggested-by: NJosh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: NKees Cook <keescook@chromium.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Hans Liljestrand <ishkamiel@gmail.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Jann Horn <jannh@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: arozansk@redhat.com Cc: axboe@kernel.dk Cc: kernel-hardening@lists.openwall.com Cc: linux-arch <linux-arch@vger.kernel.org> Link: http://lkml.kernel.org/r/1500921349-10803-3-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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