https://github.com/torvalds/linux
Revision 7b2b55da1db10a5525460633ae4b6fb0be060c41 authored by Jason Xing on 25 August 2019, 00:54:53 UTC, committed by Linus Torvalds on 25 August 2019, 02:48:42 UTC
Only when calling the poll syscall the first time can user receive POLLPRI correctly. After that, user always fails to acquire the event signal. Reproduce case: 1. Get the monitor code in Documentation/accounting/psi.txt 2. Run it, and wait for the event triggered. 3. Kill and restart the process. The question is why we can end up with poll_scheduled = 1 but the work not running (which would reset it to 0). And the answer is because the scheduling side sees group->poll_kworker under RCU protection and then schedules it, but here we cancel the work and destroy the worker. The cancel needs to pair with resetting the poll_scheduled flag. Link: http://lkml.kernel.org/r/1566357985-97781-1-git-send-email-joseph.qi@linux.alibaba.com Signed-off-by: Jason Xing <kerneljasonxing@linux.alibaba.com> Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Caspar Zhang <caspar@linux.alibaba.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent bb65f89
Tip revision: 7b2b55da1db10a5525460633ae4b6fb0be060c41 authored by Jason Xing on 25 August 2019, 00:54:53 UTC
psi: get poll_work to run when calling poll syscall next time
psi: get poll_work to run when calling poll syscall next time
Tip revision: 7b2b55d
compat_binfmt_elf.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* 32-bit compatibility support for ELF format executables and core dumps.
*
* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
*
* Red Hat Author: Roland McGrath.
*
* This file is used in a 64-bit kernel that wants to support 32-bit ELF.
* asm/elf.h is responsible for defining the compat_* and COMPAT_* macros
* used below, with definitions appropriate for 32-bit ABI compatibility.
*
* We use macros to rename the ABI types and machine-dependent
* functions used in binfmt_elf.c to compat versions.
*/
#include <linux/elfcore-compat.h>
#include <linux/time.h>
/*
* Rename the basic ELF layout types to refer to the 32-bit class of files.
*/
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
#undef elfhdr
#undef elf_phdr
#undef elf_shdr
#undef elf_note
#undef elf_addr_t
#define elfhdr elf32_hdr
#define elf_phdr elf32_phdr
#define elf_shdr elf32_shdr
#define elf_note elf32_note
#define elf_addr_t Elf32_Addr
/*
* Some data types as stored in coredump.
*/
#define user_long_t compat_long_t
#define user_siginfo_t compat_siginfo_t
#define copy_siginfo_to_user copy_siginfo_to_user32
/*
* The machine-dependent core note format types are defined in elfcore-compat.h,
* which requires asm/elf.h to define compat_elf_gregset_t et al.
*/
#define elf_prstatus compat_elf_prstatus
#define elf_prpsinfo compat_elf_prpsinfo
#undef ns_to_timeval
#define ns_to_timeval ns_to_old_timeval32
/*
* To use this file, asm/elf.h must define compat_elf_check_arch.
* The other following macros can be defined if the compat versions
* differ from the native ones, or omitted when they match.
*/
#undef ELF_ARCH
#undef elf_check_arch
#define elf_check_arch compat_elf_check_arch
#ifdef COMPAT_ELF_PLATFORM
#undef ELF_PLATFORM
#define ELF_PLATFORM COMPAT_ELF_PLATFORM
#endif
#ifdef COMPAT_ELF_HWCAP
#undef ELF_HWCAP
#define ELF_HWCAP COMPAT_ELF_HWCAP
#endif
#ifdef COMPAT_ELF_HWCAP2
#undef ELF_HWCAP2
#define ELF_HWCAP2 COMPAT_ELF_HWCAP2
#endif
#ifdef COMPAT_ARCH_DLINFO
#undef ARCH_DLINFO
#define ARCH_DLINFO COMPAT_ARCH_DLINFO
#endif
#ifdef COMPAT_ELF_ET_DYN_BASE
#undef ELF_ET_DYN_BASE
#define ELF_ET_DYN_BASE COMPAT_ELF_ET_DYN_BASE
#endif
#ifdef COMPAT_ELF_EXEC_PAGESIZE
#undef ELF_EXEC_PAGESIZE
#define ELF_EXEC_PAGESIZE COMPAT_ELF_EXEC_PAGESIZE
#endif
#ifdef COMPAT_ELF_PLAT_INIT
#undef ELF_PLAT_INIT
#define ELF_PLAT_INIT COMPAT_ELF_PLAT_INIT
#endif
#ifdef COMPAT_SET_PERSONALITY
#undef SET_PERSONALITY
#define SET_PERSONALITY COMPAT_SET_PERSONALITY
#endif
#ifdef compat_start_thread
#undef start_thread
#define start_thread compat_start_thread
#endif
#ifdef compat_arch_setup_additional_pages
#undef ARCH_HAS_SETUP_ADDITIONAL_PAGES
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
#undef arch_setup_additional_pages
#define arch_setup_additional_pages compat_arch_setup_additional_pages
#endif
/*
* Rename a few of the symbols that binfmt_elf.c will define.
* These are all local so the names don't really matter, but it
* might make some debugging less confusing not to duplicate them.
*/
#define elf_format compat_elf_format
#define init_elf_binfmt init_compat_elf_binfmt
#define exit_elf_binfmt exit_compat_elf_binfmt
/*
* We share all the actual code with the native (64-bit) version.
*/
#include "binfmt_elf.c"
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