# git rev-parse -q --verify 06af8679449d4ed282df13191fc52d5ba28ec536^{commit} 06af8679449d4ed282df13191fc52d5ba28ec536 already have revision, skipping fetch # git checkout -q -f -B kisskb 06af8679449d4ed282df13191fc52d5ba28ec536 # git clean -qxdf # < git log -1 # commit 06af8679449d4ed282df13191fc52d5ba28ec536 # Author: Eric W. Biederman # Date: Thu Jun 10 15:11:11 2021 -0500 # # coredump: Limit what can interrupt coredumps # # Olivier Langlois has been struggling with coredumps being incompletely written in # processes using io_uring. # # Olivier Langlois writes: # > io_uring is a big user of task_work and any event that io_uring made a # > task waiting for that occurs during the core dump generation will # > generate a TIF_NOTIFY_SIGNAL. # > # > Here are the detailed steps of the problem: # > 1. io_uring calls vfs_poll() to install a task to a file wait queue # > with io_async_wake() as the wakeup function cb from io_arm_poll_handler() # > 2. wakeup function ends up calling task_work_add() with TWA_SIGNAL # > 3. task_work_add() sets the TIF_NOTIFY_SIGNAL bit by calling # > set_notify_signal() # # The coredump code deliberately supports being interrupted by SIGKILL, # and depends upon prepare_signal to filter out all other signals. Now # that signal_pending includes wake ups for TIF_NOTIFY_SIGNAL this hack # in dump_emitted by the coredump code no longer works. # # Make the coredump code more robust by explicitly testing for all of # the wakeup conditions the coredump code supports. This prevents # new wakeup conditions from breaking the coredump code, as well # as fixing the current issue. # # The filesystem code that the coredump code uses already limits # itself to only aborting on fatal_signal_pending. So it should # not develop surprising wake-up reasons either. # # v2: Don't remove the now unnecessary code in prepare_signal. # # Cc: stable@vger.kernel.org # Fixes: 12db8b690010 ("entry: Add support for TIF_NOTIFY_SIGNAL") # Reported-by: Olivier Langlois # Signed-off-by: "Eric W. Biederman" # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-gcc --version # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-ld --version # < git log --format=%s --max-count=1 06af8679449d4ed282df13191fc52d5ba28ec536 # < make -s -j 120 ARCH=arm O=/kisskb/build/linus_multi_v7_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- multi_v7_defconfig # < make -s -j 120 ARCH=arm O=/kisskb/build/linus_multi_v7_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- help # make -s -j 120 ARCH=arm O=/kisskb/build/linus_multi_v7_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- olddefconfig # make -s -j 120 ARCH=arm O=/kisskb/build/linus_multi_v7_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- In file included from /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/tm.h:23, from /kisskb/src/scripts/gcc-plugins/gcc-common.h:15, from /kisskb/src/scripts/gcc-plugins/arm_ssp_per_task_plugin.c:3: /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/config/elfos.h:102:21: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix] fprintf ((FILE), "%s"HOST_WIDE_INT_PRINT_UNSIGNED"\n",\ ^ /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/config/elfos.h:170:24: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ In file included from /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/tm.h:44, from /kisskb/src/scripts/gcc-plugins/gcc-common.h:15, from /kisskb/src/scripts/gcc-plugins/arm_ssp_per_task_plugin.c:3: /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/defaults.h:126:24: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ cc1plus: warning: unrecognized command line option '-Wno-format-diag' /kisskb/src/arch/arm/crypto/ghash-ce-glue.c: In function 'ghash_do_update': /kisskb/src/arch/arm/crypto/ghash-ce-glue.c:67:44: warning: passing argument 4 of 'pmull_ghash_update_p64' from incompatible pointer type pmull_ghash_update_p64(blocks, dg, src, key->h, head); ^ /kisskb/src/arch/arm/crypto/ghash-ce-glue.c:45:17: note: expected 'const u64 (*)[2]' but argument is of type 'u64 (*)[2]' asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src, ^ /kisskb/src/arch/arm/crypto/ghash-ce-glue.c:69:43: warning: passing argument 4 of 'pmull_ghash_update_p8' from incompatible pointer type pmull_ghash_update_p8(blocks, dg, src, key->h, head); ^ /kisskb/src/arch/arm/crypto/ghash-ce-glue.c:48:17: note: expected 'const u64 (*)[2]' but argument is of type 'u64 (*)[2]' asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src, ^ /kisskb/src/net/sched/sch_frag.c: In function 'sch_fragment': /kisskb/src/net/sched/sch_frag.c:93:10: warning: missing braces around initializer [-Wmissing-braces] struct rtable sch_frag_rt = { 0 }; ^ /kisskb/src/net/sched/sch_frag.c:93:10: warning: (near initialization for 'sch_frag_rt.dst') [-Wmissing-braces] /kisskb/src/drivers/firmware/qcom_scm-smc.c: In function '__scm_smc_call': /kisskb/src/drivers/firmware/qcom_scm-smc.c:95:9: warning: missing braces around initializer [-Wmissing-braces] struct arm_smccc_args smc = {0}; ^ /kisskb/src/drivers/firmware/qcom_scm-smc.c:95:9: warning: (near initialization for 'smc.args') [-Wmissing-braces] /kisskb/src/drivers/firmware/qcom_scm-legacy.c: In function 'scm_legacy_call': /kisskb/src/drivers/firmware/qcom_scm-legacy.c:139:9: warning: missing braces around initializer [-Wmissing-braces] struct arm_smccc_args smc = {0}; ^ /kisskb/src/drivers/firmware/qcom_scm-legacy.c:139:9: warning: (near initialization for 'smc.args') [-Wmissing-braces] Completed OK # rm -rf /kisskb/build/linus_multi_v7_defconfig_arm-gcc4.9 # Build took: 0:02:06.615270