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2021-03-17scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section namesJoe Lawrence2-1/+14
commit 9c8e2f6d3d361439cc6744a094f1c15681b55269 upstream. When building with -ffunction-sections, the compiler will place each function into its own ELF section, prefixed with ".text". For example, a simple test module with functions test_module_do_work() and test_module_wq_func(): % objdump --section-headers test_module.o | awk '/\.text/{print $2}' .text .text.test_module_do_work .text.test_module_wq_func .init.text .exit.text Adjust the recordmcount scripts to look for ".text" as a section name prefix. This will ensure that those functions will be included in the __mcount_loc relocations: % objdump --reloc --section __mcount_loc test_module.o OFFSET TYPE VALUE 0000000000000000 R_X86_64_64 .text.test_module_do_work 0000000000000008 R_X86_64_64 .text.test_module_wq_func 0000000000000010 R_X86_64_64 .init.text Link: http://lkml.kernel.org/r/1542745158-25392-2-git-send-email-joe.lawrence@redhat.com Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Manoj Gupta <manojgupta@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-07scripts: set proper OpenSSL include dir also for sign-fileRolf Eike Beer1-0/+1
commit fe968c41ac4f4ec9ffe3c4cf16b72285f5e9674f upstream. Fixes: 2cea4a7a1885 ("scripts: use pkg-config to locate libcrypto") Signed-off-by: Rolf Eike Beer <eb@emlix.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-07scripts: use pkg-config to locate libcryptoRolf Eike Beer1-2/+6
commit 2cea4a7a1885bd0c765089afc14f7ff0eb77864e upstream. Otherwise build fails if the headers are not in the default location. While at it also ask pkg-config for the libs, with fallback to the existing value. Signed-off-by: Rolf Eike Beer <eb@emlix.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-03scripts/recordmcount.pl: support big endian for ARCH shRong Chen1-1/+5
[ Upstream commit 93ca696376dd3d44b9e5eae835ffbc84772023ec ] The kernel test robot reported the following issue: CC [M] drivers/soc/litex/litex_soc_ctrl.o sh4-linux-objcopy: Unable to change endianness of input file(s) sh4-linux-ld: cannot find drivers/soc/litex/.tmp_gl_litex_soc_ctrl.o: No such file or directory sh4-linux-objcopy: 'drivers/soc/litex/.tmp_mx_litex_soc_ctrl.o': No such file The problem is that the format of input file is elf32-shbig-linux, but sh4-linux-objcopy wants to output a file which format is elf32-sh-linux: $ sh4-linux-objdump -d drivers/soc/litex/litex_soc_ctrl.o | grep format drivers/soc/litex/litex_soc_ctrl.o: file format elf32-shbig-linux Link: https://lkml.kernel.org/r/20210210150435.2171567-1-rong.a.chen@intel.com Link: https://lore.kernel.org/linux-mm/202101261118.GbbYSlHu-lkp@intel.com Signed-off-by: Rong Chen <rong.a.chen@intel.com> Reported-by: kernel test robot <lkp@intel.com> Cc: Yoshinori Sato <ysato@users.osdn.me> Cc: Rich Felker <dalias@libc.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-02-23tracing: Avoid calling cc-option -mrecord-mcount for every MakefileVasily Gorbik1-6/+3
commit 07d0408120216b60625c9a5b8012d1c3a907984d upstream. Currently if CONFIG_FTRACE_MCOUNT_RECORD is enabled -mrecord-mcount compiler flag support is tested for every Makefile. Top 4 cc-option usages: 511 -mrecord-mcount 11 -fno-stack-protector 9 -Wno-override-init 2 -fsched-pressure To address that move cc-option from scripts/Makefile.build to top Makefile and export CC_USING_RECORD_MCOUNT to be used in original place. While doing that also add -mrecord-mcount to CC_FLAGS_FTRACE (if gcc actually supports it). Link: http://lkml.kernel.org/r/patch-2.thread-aa7b8d.git-de935bace15a.your-ad-here.call-01533557518-ext-9465@work.hours Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-23tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcountGreg Thelen1-1/+1
commit ed7d40bc67b8353c677b38c6cdddcdc310c0f452 upstream. Non gcc-5 builds with CONFIG_STACK_VALIDATION=y and SKIP_STACK_VALIDATION=1 fail. Example output: /bin/sh: init/.tmp_main.o: Permission denied commit 96f60dfa5819 ("trace: Use -mcount-record for dynamic ftrace"), added a mismatched endif. This causes cmd_objtool to get mistakenly set. Relocate endif to balance the newly added -record-mcount check. Link: http://lkml.kernel.org/r/20180608214746.136554-1-gthelen@google.com Fixes: 96f60dfa5819 ("trace: Use -mcount-record for dynamic ftrace") Acked-by: Andi Kleen <ak@linux.intel.com> Tested-by: David Rientjes <rientjes@google.com> Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-23trace: Use -mcount-record for dynamic ftraceAndi Kleen1-0/+6
commit 96f60dfa5819a065bfdd2f2ba0df7d9cbce7f4dd upstream. gcc 5 supports a new -mcount-record option to generate ftrace tables directly. This avoids the need to run record_mcount manually. Use this option when available. So far doesn't use -mcount-nop, which also exists now. This is needed to make ftrace work with LTO because the normal record-mcount script doesn't run over the link time output. It should also improve build times slightly in the general case. Link: http://lkml.kernel.org/r/20171127213423.27218-12-andi@firstfloor.org Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-12depmod: handle the case of /sbin/depmod without /sbin in PATHLinus Torvalds1-0/+2
[ Upstream commit cedd1862be7e666be87ec824dabc6a2b05618f36 ] Commit 436e980e2ed5 ("kbuild: don't hardcode depmod path") stopped hard-coding the path of depmod, but in the process caused trouble for distributions that had that /sbin location, but didn't have it in the PATH (generally because /sbin is limited to the super-user path). Work around it for now by just adding /sbin to the end of PATH in the depmod.sh script. Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-12-29checkpatch: fix unescaped left braceDwaipayan Ray1-1/+1
[ Upstream commit 03f4935135b9efeb780b970ba023c201f81cf4e6 ] There is an unescaped left brace in a regex in OPEN_BRACE check. This throws a runtime error when checkpatch is run with --fix flag and the OPEN_BRACE check is executed. Fix it by escaping the left brace. Link: https://lkml.kernel.org/r/20201115202928.81955-1-dwaipayanray1@gmail.com Fixes: 8d1824780f2f ("checkpatch: add --fix option for a couple OPEN_BRACE misuses") Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com> Acked-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-05scripts/setlocalversion: make git describe output more reliableRasmus Villemoes1-5/+16
commit 548b8b5168c90c42e88f70fcf041b4ce0b8e7aa8 upstream. When building for an embedded target using Yocto, we're sometimes observing that the version string that gets built into vmlinux (and thus what uname -a reports) differs from the path under /lib/modules/ where modules get installed in the rootfs, but only in the length of the -gabc123def suffix. Hence modprobe always fails. The problem is that Yocto has the concept of "sstate" (shared state), which allows different developers/buildbots/etc. to share build artifacts, based on a hash of all the metadata that went into building that artifact - and that metadata includes all dependencies (e.g. the compiler used etc.). That normally works quite well; usually a clean build (without using any sstate cache) done by one developer ends up being binary identical to a build done on another host. However, one thing that can cause two developers to end up with different builds [and thus make one's vmlinux package incompatible with the other's kernel-dev package], which is not captured by the metadata hashing, is this `git describe`: The output of that can be affected by (1) git version: before 2.11 git defaulted to a minimum of 7, since 2.11 (git.git commit e6c587) the default is dynamic based on the number of objects in the repo (2) hence even if both run the same git version, the output can differ based on how many remotes are being tracked (or just lots of local development branches or plain old garbage) (3) and of course somebody could have a core.abbrev config setting in ~/.gitconfig So in order to avoid `uname -a` output relying on such random details of the build environment which are rather hard to ensure are consistent between developers and buildbots, make sure the abbreviated sha1 always consists of exactly 12 hex characters. That is consistent with the current rule for -stable patches, and is almost always enough to identify the head commit unambigously - in the few cases where it does not, the v5.4.3-00021- prefix would certainly nail it down. [Adapt to `` vs $() differences between 5.4 and upstream.] Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-09checkpatch: fix the usage of capture group ( ... )Mrinal Pandey1-2/+2
commit 13e45417cedbfc44b1926124b1846f5ee8c6ba4a upstream. The usage of "capture group (...)" in the immediate condition after `&&` results in `$1` being uninitialized. This issues a warning "Use of uninitialized value $1 in regexp compilation at ./scripts/checkpatch.pl line 2638". I noticed this bug while running checkpatch on the set of commits from v5.7 to v5.8-rc1 of the kernel on the commits with a diff content in their commit message. This bug was introduced in the script by commit e518e9a59ec3 ("checkpatch: emit an error when there's a diff in a changelog"). It has been in the script since then. The author intended to store the match made by capture group in variable `$1`. This should have contained the name of the file as `[\w/]+` matched. However, this couldn't be accomplished due to usage of capture group and `$1` in the same regular expression. Fix this by placing the capture group in the condition before `&&`. Thus, `$1` can be initialized to the text that capture group matches thereby setting it to the desired and required value. Fixes: e518e9a59ec3 ("checkpatch: emit an error when there's a diff in a changelog") Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Reviewed-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Joe Perches <joe@perches.com> Link: https://lkml.kernel.org/r/20200714032352.f476hanaj2dlmiot@mrinalpandey Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29scripts/decode_stacktrace: strip basepath from all pathsPi-Hsun Shih1-2/+2
[ Upstream commit d178770d8d21489abf5bafefcbb6d5243b482e9a ] Currently the basepath is removed only from the beginning of the string. When the symbol is inlined and there's multiple line outputs of addr2line, only the first line would have basepath removed. Change to remove the basepath prefix from all lines. Fixes: 31013836a71e ("scripts/decode_stacktrace: match basepath using shell prefix operator, not regex") Co-developed-by: Shik Chen <shik@chromium.org> Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org> Signed-off-by: Shik Chen <shik@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Nicolas Boichat <drinkcat@chromium.org> Cc: Jiri Slaby <jslaby@suse.cz> Link: http://lkml.kernel.org/r/20200720082709.252805-1-pihsun@chromium.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-30kbuild: improve cc-option to clean up all temporary filesMasahiro Yamada1-5/+6
[ Upstream commit f2f02ebd8f3833626642688b2d2c6a7b3c141fa9 ] When cc-option and friends evaluate compiler flags, the temporary file $$TMP is created as an output object, and automatically cleaned up. The actual file path of $$TMP is .<pid>.tmp, here <pid> is the process ID of $(shell ...) invoked from cc-option. (Please note $$$$ is the escape sequence of $$). Such garbage files are cleaned up in most cases, but some compiler flags create additional output files. For example, -gsplit-dwarf creates a .dwo file. When CONFIG_DEBUG_INFO_SPLIT=y, you will see a bunch of .<pid>.dwo files left in the top of build directories. You may not notice them unless you do 'ls -a', but the garbage files will increase every time you run 'make'. This commit changes the temporary object path to .tmp_<pid>/tmp, and removes .tmp_<pid> directory when exiting. Separate build artifacts such as *.dwo will be cleaned up all together because their file paths are usually determined based on the base name of the object. Another example is -ftest-coverage, which outputs the coverage data into <base-name-of-object>.gcno Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-25mksysmap: Fix the mismatch of '.L' symbols in System.mapashimida1-1/+1
[ Upstream commit 72d24accf02add25e08733f0ecc93cf10fcbd88c ] When System.map was generated, the kernel used mksysmap to filter the kernel symbols, but all the symbols with the second letter 'L' in the kernel were filtered out, not just the symbols starting with 'dot + L'. For example: ashimida@ubuntu:~/linux$ cat System.map |grep ' .L' ashimida@ubuntu:~/linux$ nm -n vmlinux |grep ' .L' ffff0000088028e0 t bLength_show ...... ffff0000092e0408 b PLLP_OUTC_lock ffff0000092e0410 b PLLP_OUTA_lock The original intent should be to filter out all local symbols starting with '.L', so the dot should be escaped. Fixes: 00902e984732 ("mksysmap: Add h8300 local symbol pattern") Signed-off-by: ashimida <ashimida@linux.alibaba.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-27gcc-common.h: Update for GCC 10Frédéric Pierret (fepitre)2-0/+5
[ Upstream commit c7527373fe28f97d8a196ab562db5589be0d34b9 ] Remove "params.h" include, which has been dropped in GCC 10. Remove is_a_helper() macro, which is now defined in gimple.h, as seen when running './scripts/gcc-plugin.sh g++ g++ gcc': In file included from <stdin>:1: ./gcc-plugins/gcc-common.h:852:13: error: redefinition of ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ 852 | inline bool is_a_helper<const ggoto *>::test(const_gimple gs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ./gcc-plugins/gcc-common.h:125, from <stdin>:1: /usr/lib/gcc/x86_64-redhat-linux/10/plugin/include/gimple.h:1037:1: note: ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ previously declared here 1037 | is_a_helper <const ggoto *>::test (const gimple *gs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ Add -Wno-format-diag to scripts/gcc-plugins/Makefile to avoid meaningless warnings from error() formats used by plugins: scripts/gcc-plugins/structleak_plugin.c: In function ‘int plugin_init(plugin_name_args*, plugin_gcc_version*)’: scripts/gcc-plugins/structleak_plugin.c:253:12: warning: unquoted sequence of 2 consecutive punctuation characters ‘'-’ in format [-Wformat-diag] 253 | error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Frédéric Pierret (fepitre) <frederic.pierret@qubes-os.org> Link: https://lore.kernel.org/r/20200407113259.270172-1-frederic.pierret@qubes-os.org [kees: include -Wno-format-diag for plugin builds] Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-20scripts/decodecode: fix trapping instruction formattingIvan Delalande1-1/+1
commit e08df079b23e2e982df15aa340bfbaf50f297504 upstream. If the trapping instruction contains a ':', for a memory access through segment registers for example, the sed substitution will insert the '*' marker in the middle of the instruction instead of the line address: 2b: 65 48 0f c7 0f cmpxchg16b %gs:*(%rdi) <-- trapping instruction I started to think I had forgotten some quirk of the assembly syntax before noticing that it was actually coming from the script. Fix it to add the address marker at the right place for these instructions: 28: 49 8b 06 mov (%r14),%rax 2b:* 65 48 0f c7 0f cmpxchg16b %gs:(%rdi) <-- trapping instruction 30: 0f 94 c0 sete %al Fixes: 18ff44b189e2 ("scripts/decodecode: make faulting insn ptr more robust") Signed-off-by: Ivan Delalande <colona@arista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200419223653.GA31248@visor Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10scripts/config: allow colons in option strings for sedJeremie Francois (on alpha)1-1/+4
[ Upstream commit e461bc9f9ab105637b86065d24b0b83f182d477c ] Sed broke on some strings as it used colon as a separator. I made it more robust by using \001, which is legit POSIX AFAIK. E.g. ./config --set-str CONFIG_USBNET_DEVADDR "de:ad:be:ef:00:01" failed with: sed: -e expression #1, char 55: unknown option to `s' Signed-off-by: Jeremie Francois (on alpha) <jeremie.francois@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-02scripts/dtc: Remove redundant YYLOC global declarationDirk Mueller2-2/+0
commit e33a814e772cdc36436c8c188d8c42d019fda639 upstream. gcc 10 will default to -fno-common, which causes this error at link time: (.text+0x0): multiple definition of `yylloc'; dtc-lexer.lex.o (symbol from plugin):(.text+0x0): first defined here This is because both dtc-lexer as well as dtc-parser define the same global symbol yyloc. Before with -fcommon those were merged into one defintion. The proper solution would be to to mark this as "extern", however that leads to: dtc-lexer.l:26:16: error: redundant redeclaration of 'yylloc' [-Werror=redundant-decls] 26 | extern YYLTYPE yylloc; | ^~~~~~ In file included from dtc-lexer.l:24: dtc-parser.tab.h:127:16: note: previous declaration of 'yylloc' was here 127 | extern YYLTYPE yylloc; | ^~~~~~ cc1: all warnings being treated as errors which means the declaration is completely redundant and can just be dropped. Signed-off-by: Dirk Mueller <dmueller@suse.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> [robh: cherry-pick from upstream] Cc: stable@vger.kernel.org Signed-off-by: Rob Herring <robh@kernel.org> [nc: Also apply to dtc-lexer.lex.c_shipped due to a lack of e039139be8c2, where dtc-lexer.l started being used] Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-02kbuild: Disable -Wpointer-to-enum-castNathan Chancellor1-0/+1
commit 82f2bc2fcc0160d6f82dd1ac64518ae0a4dd183f upstream. Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when casting to enums. The kernel does this in certain places, such as device tree matches to set the version of the device being used, which allows the kernel to avoid using a gigantic union. https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428 https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402 https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264 To avoid a ton of false positive warnings, disable this particular part of the warning, which has been split off into a separate diagnostic so that the entire warning does not need to be turned off for clang. It will be visible under W=1 in case people want to go about fixing these easily and enabling the warning treewide. Cc: stable@vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/887 Link: https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-02parse-maintainers: Mark as executableJonathan Neuschäfer1-0/+0
[ Upstream commit 611d61f9ac99dc9e1494473fb90117a960a89dfa ] This makes the script more convenient to run. Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-28kconfig: fix broken dependency in randconfig-generated .configMasahiro Yamada1-1/+1
[ Upstream commit c8fb7d7e48d11520ad24808cfce7afb7b9c9f798 ] Running randconfig on arm64 using KCONFIG_SEED=0x40C5E904 (e.g. on v5.5) produces the .config with CONFIG_EFI=y and CONFIG_CPU_BIG_ENDIAN=y, which does not meet the !CONFIG_CPU_BIG_ENDIAN dependency. This is because the user choice for CONFIG_CPU_LITTLE_ENDIAN vs CONFIG_CPU_BIG_ENDIAN is set by randomize_choice_values() after the value of CONFIG_EFI is calculated. When this happens, the has_changed flag should be set. Currently, it takes the result from the last iteration. It should accumulate all the results of the loop. Fixes: 3b9a19e08960 ("kconfig: loop as long as we changed some symbols in randconfig") Reported-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-29ARM: 8950/1: ftrace/recordmcount: filter relocation typesAlex Sverdlin1-0/+17
commit 927d780ee371d7e121cea4fc7812f6ef2cea461c upstream. Scenario 1, ARMv7 ================= If code in arch/arm/kernel/ftrace.c would operate on mcount() pointer the following may be generated: 00000230 <prealloc_fixed_plts>: 230: b5f8 push {r3, r4, r5, r6, r7, lr} 232: b500 push {lr} 234: f7ff fffe bl 0 <__gnu_mcount_nc> 234: R_ARM_THM_CALL __gnu_mcount_nc 238: f240 0600 movw r6, #0 238: R_ARM_THM_MOVW_ABS_NC __gnu_mcount_nc 23c: f8d0 1180 ldr.w r1, [r0, #384] ; 0x180 FTRACE currently is not able to deal with it: WARNING: CPU: 0 PID: 0 at .../kernel/trace/ftrace.c:1979 ftrace_bug+0x1ad/0x230() ... CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.116-... #1 ... [<c0314e3d>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14) [<c03115e9>] (show_stack) from [<c051a7f1>] (dump_stack+0x81/0xa8) [<c051a7f1>] (dump_stack) from [<c0321c5d>] (warn_slowpath_common+0x69/0x90) [<c0321c5d>] (warn_slowpath_common) from [<c0321cf3>] (warn_slowpath_null+0x17/0x1c) [<c0321cf3>] (warn_slowpath_null) from [<c038ee9d>] (ftrace_bug+0x1ad/0x230) [<c038ee9d>] (ftrace_bug) from [<c038f1f9>] (ftrace_process_locs+0x27d/0x444) [<c038f1f9>] (ftrace_process_locs) from [<c08915bd>] (ftrace_init+0x91/0xe8) [<c08915bd>] (ftrace_init) from [<c0885a67>] (start_kernel+0x34b/0x358) [<c0885a67>] (start_kernel) from [<00308095>] (0x308095) ---[ end trace cb88537fdc8fa200 ]--- ftrace failed to modify [<c031266c>] prealloc_fixed_plts+0x8/0x60 actual: 44:f2:e1:36 ftrace record flags: 0 (0) expected tramp: c03143e9 Scenario 2, ARMv4T ================== ftrace: allocating 14435 entries in 43 pages ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:2029 ftrace_bug+0x204/0x310 CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.5 #1 Hardware name: Cirrus Logic EDB9302 Evaluation Board [<c0010a24>] (unwind_backtrace) from [<c000ecb0>] (show_stack+0x20/0x2c) [<c000ecb0>] (show_stack) from [<c03c72e8>] (dump_stack+0x20/0x30) [<c03c72e8>] (dump_stack) from [<c0021c18>] (__warn+0xdc/0x104) [<c0021c18>] (__warn) from [<c0021d7c>] (warn_slowpath_null+0x4c/0x5c) [<c0021d7c>] (warn_slowpath_null) from [<c0095360>] (ftrace_bug+0x204/0x310) [<c0095360>] (ftrace_bug) from [<c04dabac>] (ftrace_init+0x3b4/0x4d4) [<c04dabac>] (ftrace_init) from [<c04cef4c>] (start_kernel+0x20c/0x410) [<c04cef4c>] (start_kernel) from [<00000000>] ( (null)) ---[ end trace 0506a2f5dae6b341 ]--- ftrace failed to modify [<c000c350>] perf_trace_sys_exit+0x5c/0xe8 actual: 1e:ff:2f:e1 Initializing ftrace call sites ftrace record flags: 0 (0) expected tramp: c000fb24 The analysis for this problem has been already performed previously, refer to the link below. Fix the above problems by allowing only selected reloc types in __mcount_loc. The list itself comes from the legacy recordmcount.pl script. Link: https://lore.kernel.org/lkml/56961010.6000806@pengutronix.de/ Cc: stable@vger.kernel.org Fixes: ed60453fa8f8 ("ARM: 6511/1: ftrace: add ARM support for C version of recordmcount") Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-12kconfig: don't crash on NULL expressions in expr_eq()Thomas Hebb1-0/+7
[ Upstream commit 272a72103012862e3a24ea06635253ead0b6e808 ] NULL expressions are taken to always be true, as implemented by the expr_is_yes() macro and by several other functions in expr.c. As such, they ought to be valid inputs to expr_eq(), which compares two expressions. Signed-off-by: Thomas Hebb <tommyhebb@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-04scripts/kallsyms: fix definitely-lost memory leakMasahiro Yamada1-0/+2
[ Upstream commit 21915eca088dc271c970e8351290e83d938114ac ] build_initial_tok_table() overwrites unused sym_entry to shrink the table size. Before the entry is overwritten, table[i].sym must be freed since it is malloc'ed data. This fixes the 'definitely lost' report from valgrind. I ran valgrind against x86_64_defconfig of v5.4-rc8 kernel, and here is the summary: [Before the fix] LEAK SUMMARY: definitely lost: 53,184 bytes in 2,874 blocks [After the fix] LEAK SUMMARY: definitely lost: 0 bytes in 0 blocks Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-17modpost: skip ELF local symbols during section mismatch checkPaul Walmsley1-0/+12
[ Upstream commit a4d26f1a0958bb1c2b60c6f1e67c6f5d43e2647b ] During development of a serial console driver with a gcc 8.2.0 toolchain for RISC-V, the following modpost warning appeared: ---- WARNING: vmlinux.o(.data+0x19b10): Section mismatch in reference from the variable .LANCHOR1 to the function .init.text:sifive_serial_console_setup() The variable .LANCHOR1 references the function __init sifive_serial_console_setup() If the reference is valid then annotate the variable with __init* or __refdata (see linux/init.h) or name the variable: *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console ---- ".LANCHOR1" is an ELF local symbol, automatically created by gcc's section anchor generation code: https://gcc.gnu.org/onlinedocs/gccint/Anchored-Addresses.html https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/varasm.c;h=cd9591a45617464946dcf9a126dde277d9de9804;hb=9fb89fa845c1b2e0a18d85ada0b077c84508ab78#l7473 This was verified by compiling the kernel with -fno-section-anchors and observing that the ".LANCHOR1" ELF local symbol disappeared, and modpost no longer warned about the section mismatch. The serial driver code idiom triggering the warning is standard Linux serial driver practice that has a specific whitelist inclusion in modpost.c. I'm neither a modpost nor an ELF expert, but naively, it doesn't seem useful for modpost to report section mismatch warnings caused by ELF local symbols by default. Local symbols have compiler-generated names, and thus bypass modpost's whitelisting algorithm, which relies on the presence of a non-autogenerated symbol name. This increases the likelihood that false positive warnings will be generated (as in the above case). Thus, disable section mismatch reporting on ELF local symbols. The rationale here is similar to that of commit 2e3a10a1551d ("ARM: avoid ARM binutils leaking ELF local symbols") and of similar code already present in modpost.c: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/mod/modpost.c?h=v4.19-rc4&id=7876320f88802b22d4e2daf7eb027dd14175a0f8#n1256 This third version of the patch implements a suggestion from Masahiro Yamada <yamada.masahiro@socionext.com> to restructure the code as an additional pattern matching step inside secref_whitelist(), and further improves the patch description. Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com> Signed-off-by: Paul Walmsley <paul@pwsan.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-05scripts/gdb: fix debugging modules compiled with hot/cold partitioningIlya Leoshkevich1-1/+2
[ Upstream commit 8731acc5068eb3f422a45c760d32198175c756f8 ] gcc's -freorder-blocks-and-partition option makes it group frequently and infrequently used code in .text.hot and .text.unlikely sections respectively. At least when building modules on s390, this option is used by default. gdb assumes that all code is located in .text section, and that .text section is located at module load address. With such modules this is no longer the case: there is code in .text.hot and .text.unlikely, and either of them might precede .text. Fix by explicitly telling gdb the addresses of code sections. It might be tempting to do this for all sections, not only the ones in the white list. Unfortunately, gdb appears to have an issue, when telling it about e.g. loadable .note.gnu.build-id section causes it to think that non-loadable .note.Linux section is loaded at address 0, which in turn causes NULL pointers to be resolved to bogus symbols. So keep using the white list approach for the time being. Link: http://lkml.kernel.org/r/20191028152734.13065-1-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-06scripts/setlocalversion: Improve -dirty check with git-status ↵Brian Norris1-2/+10
--no-optional-locks [ Upstream commit ff64dd4857303dd5550faed9fd598ac90f0f2238 ] git-diff-index does not refresh the index for you, so using it for a "-dirty" check can give misleading results. Commit 6147b1cf19651 ("scripts/setlocalversion: git: Make -dirty check more robust") tried to fix this by switching to git-status, but it overlooked the fact that git-status also writes to the .git directory of the source tree, which is definitely not kosher for an out-of-tree (O=) build. That is getting reverted. Fortunately, git-status now supports avoiding writing to the index via the --no-optional-locks flag, as of git 2.14. It still calculates an up-to-date index, but it avoids writing it out to the .git directory. So, let's retry the solution from commit 6147b1cf19651 using this new flag first, and if it fails, we assume this is an older version of git and just use the old git-diff-index method. It's hairy to get the 'grep -vq' (inverted matching) correct by stashing the output of git-status (you have to be careful about the difference betwen "empty stdin" and "blank line on stdin"), so just pipe the output directly to grep and use a regex that's good enough for both the git-status and git-diff-index version. Cc: Christian Kujau <lists@nerdbynature.de> Cc: Guenter Roeck <linux@roeck-us.net> Suggested-by: Alexander Kapshuk <alexander.kapshuk@gmail.com> Signed-off-by: Brian Norris <briannorris@chromium.org> Tested-by: Genki Sky <sky@genki.is> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-29namespace: fix namespace.pl script to support relative pathsJacob Keller1-6/+7
[ Upstream commit 82fdd12b95727640c9a8233c09d602e4518e71f7 ] The namespace.pl script does not work properly if objtree is not set to an absolute path. The do_nm function is run from within the find function, which changes directories. Because of this, appending objtree, $File::Find::dir, and $source, will return a path which is not valid from the current directory. This used to work when objtree was set to an absolute path when using "make namespacecheck". It appears to have not worked when calling ./scripts/namespace.pl directly. This behavior was changed in 7e1c04779efd ("kbuild: Use relative path for $(objtree)", 2014-05-14) Rather than fixing the Makefile to set objtree to an absolute path, just fix namespace.pl to work when srctree and objtree are relative. Also fix the script to use an absolute path for these by default. Use the File::Spec module for this purpose. It's been part of perl 5 since 5.005. The curdir() function is used to get the current directory when the objtree and srctree aren't set in the environment. rel2abs() is used to convert possibly relative objtree and srctree environment variables to absolute paths. Finally, the catfile() function is used instead of string appending paths together, since this is more robust when joining paths together. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-05randstruct: Check member structs in is_pure_ops_struct()Joonwon Kang1-5/+5
commit 60f2c82ed20bde57c362e66f796cf9e0e38a6dbb upstream. While no uses in the kernel triggered this case, it was possible to have a false negative where a struct contains other structs which contain only function pointers because of unreachable code in is_pure_ops_struct(). Signed-off-by: Joonwon Kang <kjw1627@gmail.com> Link: https://lore.kernel.org/r/20190727155841.GA13586@host Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-16scripts/decode_stacktrace: match basepath using shell prefix operator, not regexNicolas Boichat1-1/+1
[ Upstream commit 31013836a71e07751a6827f9d2ad41ef502ddaff ] The basepath may contain special characters, which would confuse the regex matcher. ${var#prefix} does the right thing. Link: http://lkml.kernel.org/r/20190518055946.181563-1-drinkcat@chromium.org Fixes: 67a28de47faa8358 ("scripts/decode_stacktrace: only strip base path when a prefix of the path") Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-25kbuild: modpost: handle KBUILD_EXTRA_SYMBOLS only for external modulesMasahiro Yamada1-1/+1
[ Upstream commit cb4819934a7f9b87876f11ed05b8624c0114551b ] KBUILD_EXTRA_SYMBOLS makes sense only when building external modules. Moreover, the modpost sets 'external_module' if the -e option is given. I replaced $(patsubst %, -e %,...) with simpler $(addprefix -e,...) while I was here. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-16scripts/sphinx-pre-install: fix script for RHEL/CentOSMauro Carvalho Chehab1-1/+1
[ Upstream commit b308467c916aa7acc5069802ab76a9f657434701 ] There's a missing parenthesis at the script, with causes it to fail to detect non-Fedora releases (e. g. RHEL/CentOS). Tested with Centos 7.6.1810. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31kallsyms: exclude kasan local symbols on s390Vasily Gorbik1-0/+3
[ Upstream commit 33177f01ca3fe550146bb9001bec2fd806b2f40c ] gcc asan instrumentation emits the following sequence to store frame pc when the kernel is built with CONFIG_RELOCATABLE: debug/vsprintf.s: .section .data.rel.ro.local,"aw" .align 8 .LC3: .quad .LASANPC4826@GOTOFF .text .align 8 .type number, @function number: .LASANPC4826: and in case reloc is issued for LASANPC label it also gets into .symtab with the same address as actual function symbol: $ nm -n vmlinux | grep 0000000001397150 0000000001397150 t .LASANPC4826 0000000001397150 t number In the end kernel backtraces are almost unreadable: [ 143.748476] Call Trace: [ 143.748484] ([<000000002da3e62c>] .LASANPC2671+0x114/0x190) [ 143.748492] [<000000002eca1a58>] .LASANPC2612+0x110/0x160 [ 143.748502] [<000000002de9d830>] print_address_description+0x80/0x3b0 [ 143.748511] [<000000002de9dd64>] __kasan_report+0x15c/0x1c8 [ 143.748521] [<000000002ecb56d4>] strrchr+0x34/0x60 [ 143.748534] [<000003ff800a9a40>] kasan_strings+0xb0/0x148 [test_kasan] [ 143.748547] [<000003ff800a9bba>] kmalloc_tests_init+0xe2/0x528 [test_kasan] [ 143.748555] [<000000002da2117c>] .LASANPC4069+0x354/0x748 [ 143.748563] [<000000002dbfbb16>] do_init_module+0x136/0x3b0 [ 143.748571] [<000000002dbff3f4>] .LASANPC3191+0x2164/0x25d0 [ 143.748580] [<000000002dbffc4c>] .LASANPC3196+0x184/0x1b8 [ 143.748587] [<000000002ecdf2ec>] system_call+0xd8/0x2d8 Since LASANPC labels are not even unique and get into .symtab only due to relocs filter them out in kallsyms. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31recordmcount: Fix spurious mcount entries on powerpcNaveen N. Rao1-1/+2
[ Upstream commit 80e5302e4bc85a6b685b7668c36c6487b5f90e9a ] An impending change to enable HAVE_C_RECORDMCOUNT on powerpc leads to warnings such as the following: # modprobe kprobe_example ftrace-powerpc: Not expected bl: opcode is 3c4c0001 WARNING: CPU: 0 PID: 227 at kernel/trace/ftrace.c:2001 ftrace_bug+0x90/0x318 Modules linked in: CPU: 0 PID: 227 Comm: modprobe Not tainted 5.2.0-rc6-00678-g1c329100b942 #2 NIP: c000000000264318 LR: c00000000025d694 CTR: c000000000f5cd30 REGS: c000000001f2b7b0 TRAP: 0700 Not tainted (5.2.0-rc6-00678-g1c329100b942) MSR: 900000010282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]> CR: 28228222 XER: 00000000 CFAR: c0000000002642fc IRQMASK: 0 <snip> NIP [c000000000264318] ftrace_bug+0x90/0x318 LR [c00000000025d694] ftrace_process_locs+0x4f4/0x5e0 Call Trace: [c000000001f2ba40] [0000000000000004] 0x4 (unreliable) [c000000001f2bad0] [c00000000025d694] ftrace_process_locs+0x4f4/0x5e0 [c000000001f2bb90] [c00000000020ff10] load_module+0x25b0/0x30c0 [c000000001f2bd00] [c000000000210cb0] sys_finit_module+0xc0/0x130 [c000000001f2be20] [c00000000000bda4] system_call+0x5c/0x70 Instruction dump: 419e0018 2f83ffff 419e00bc 2f83ffea 409e00cc 4800001c 0fe00000 3c62ff96 39000001 39400000 386386d0 480000c4 <0fe00000> 3ce20003 39000001 3c62ff96 ---[ end trace 4c438d5cebf78381 ]--- ftrace failed to modify [<c0080000012a0008>] 0xc0080000012a0008 actual: 01:00:4c:3c Initializing ftrace call sites ftrace record flags: 2000000 (0) expected tramp: c00000000006af4c Looking at the relocation records in __mcount_loc shows a few spurious entries: RELOCATION RECORDS FOR [__mcount_loc]: OFFSET TYPE VALUE 0000000000000000 R_PPC64_ADDR64 .text.unlikely+0x0000000000000008 0000000000000008 R_PPC64_ADDR64 .text.unlikely+0x0000000000000014 0000000000000010 R_PPC64_ADDR64 .text.unlikely+0x0000000000000060 0000000000000018 R_PPC64_ADDR64 .text.unlikely+0x00000000000000b4 0000000000000020 R_PPC64_ADDR64 .init.text+0x0000000000000008 0000000000000028 R_PPC64_ADDR64 .init.text+0x0000000000000014 The first entry in each section is incorrect. Looking at the relocation records, the spurious entries correspond to the R_PPC64_ENTRY records: RELOCATION RECORDS FOR [.text.unlikely]: OFFSET TYPE VALUE 0000000000000000 R_PPC64_REL64 .TOC.-0x0000000000000008 0000000000000008 R_PPC64_ENTRY *ABS* 0000000000000014 R_PPC64_REL24 _mcount <snip> The problem is that we are not validating the return value from get_mcountsym() in sift_rel_mcount(). With this entry, mcountsym is 0, but Elf_r_sym(relp) also ends up being 0. Fix this by ensuring mcountsym is valid before processing the entry. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Tested-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-10scripts/decode_stacktrace.sh: prefix addr2line with $CROSS_COMPILEManuel Traut1-1/+1
[ Upstream commit c04e32e911653442fc834be6e92e072aeebe01a1 ] At least for ARM64 kernels compiled with the crosstoolchain from Debian/stretch or with the toolchain from kernel.org the line number is not decoded correctly by 'decode_stacktrace.sh': $ echo "[ 136.513051] f1+0x0/0xc [kcrash]" | \ CROSS_COMPILE=/opt/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux- \ ./scripts/decode_stacktrace.sh /scratch/linux-arm64/vmlinux \ /scratch/linux-arm64 \ /nfs/debian/lib/modules/4.20.0-devel [ 136.513051] f1 (/linux/drivers/staging/kcrash/kcrash.c:68) kcrash If addr2line from the toolchain is used the decoded line number is correct: [ 136.513051] f1 (/linux/drivers/staging/kcrash/kcrash.c:57) kcrash Link: http://lkml.kernel.org/r/20190527083425.3763-1-manut@linutronix.de Signed-off-by: Manuel Traut <manut@linutronix.de> Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-25scripts/checkstack.pl: Fix arm64 wrong or unknown architectureGeorge G. Davis1-1/+1
[ Upstream commit 4f45d62a52297b10ded963412a158685647ecdec ] The following error occurs for the `make ARCH=arm64 checkstack` case: aarch64-linux-gnu-objdump -d vmlinux $(find . -name '*.ko') | \ perl ./scripts/checkstack.pl arm64 wrong or unknown architecture "arm64" As suggested by Masahiro Yamada, fix the above error using regular expressions in the same way it was fixed for the `ARCH=x86` case via commit fda9f9903be6 ("scripts/checkstack.pl: automatically handle 32-bit and 64-bit mode for ARCH=x86"). Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: George G. Davis <george_davis@mentor.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-11fs: stream_open - opener for stream-like files so that read and write can ↵Kirill Smelkov1-0/+363
run simultaneously without deadlock commit 10dce8af34226d90fa56746a934f8da5dcdba3df upstream. Commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per POSIX") added locking for file.f_pos access and in particular made concurrent read and write not possible - now both those functions take f_pos lock for the whole run, and so if e.g. a read is blocked waiting for data, write will deadlock waiting for that read to complete. This caused regression for stream-like files where previously read and write could run simultaneously, but after that patch could not do so anymore. See e.g. commit 581d21a2d02a ("xenbus: fix deadlock on writes to /proc/xen/xenbus") which fixes such regression for particular case of /proc/xen/xenbus. The patch that added f_pos lock in 2014 did so to guarantee POSIX thread safety for read/write/lseek and added the locking to file descriptors of all regular files. In 2014 that thread-safety problem was not new as it was already discussed earlier in 2006. However even though 2006'th version of Linus's patch was adding f_pos locking "only for files that are marked seekable with FMODE_LSEEK (thus avoiding the stream-like objects like pipes and sockets)", the 2014 version - the one that actually made it into the tree as 9c225f2655e3 - is doing so irregardless of whether a file is seekable or not. See https://lore.kernel.org/lkml/53022DB1.4070805@gmail.com/ https://lwn.net/Articles/180387 https://lwn.net/Articles/180396 for historic context. The reason that it did so is, probably, that there are many files that are marked non-seekable, but e.g. their read implementation actually depends on knowing current position to correctly handle the read. Some examples: