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From: Adhemerval Zanella <azanella@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc/azanella/bz12683] nptl: x86_64: Fix Race conditions in pthread cancellation (BZ#12683) Date: Thu, 17 Oct 2019 13:57:00 -0000 [thread overview] Message-ID: <20191017135702.90057.qmail@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=67911f4199774950c4b08def038c17f567032735 commit 67911f4199774950c4b08def038c17f567032735 Author: Adhemerval Zanella <adhemerval.zanella@linaro.org> Date: Mon Sep 29 09:48:34 2014 -0300 nptl: x86_64: Fix Race conditions in pthread cancellation (BZ#12683) This patches adds the x86_64 modification required for the BZ#12683. The arch-specific {libc-,librt-}cancelation.S files are remove in favor of the default libc-cancellation implementation, the TCB_CANCELING_BITMASK is remove since it is now unused, and the arch-specific syscall_cancel is provided. Checked on x86_64-linux-gnu. Diff: --- sysdeps/unix/sysv/linux/x86_64/cancellation.S | 104 --------------------- sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S | 21 ----- .../unix/sysv/linux/x86_64/librt-cancellation.S | 21 ----- sysdeps/unix/sysv/linux/x86_64/syscall_cancel.S | 59 ++++++++++++ sysdeps/x86_64/nptl/tcb-offsets.sym | 11 +-- 5 files changed, 61 insertions(+), 155 deletions(-) diff --git a/sysdeps/unix/sysv/linux/x86_64/cancellation.S b/sysdeps/unix/sysv/linux/x86_64/cancellation.S deleted file mode 100644 index f8a142d..0000000 --- a/sysdeps/unix/sysv/linux/x86_64/cancellation.S +++ /dev/null @@ -1,104 +0,0 @@ -/* Copyright (C) 2009-2019 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Ulrich Drepper <drepper@redhat.com>, 2009. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#include <sysdep.h> -#include <tcb-offsets.h> -#include <kernel-features.h> -#include <lowlevellock-futex.h> - -#define PTHREAD_UNWIND JUMPTARGET(__pthread_unwind) -#if IS_IN (libpthread) -# if defined SHARED && !defined NO_HIDDEN -# undef PTHREAD_UNWIND -# define PTHREAD_UNWIND __GI___pthread_unwind -# endif -#else -# ifndef SHARED - .weak __pthread_unwind -# endif -#endif - - -#define LOAD_PRIVATE_FUTEX_WAIT(reg) \ - movl $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg - -/* It is crucial that the functions in this file don't modify registers - other than %rax and %r11. The syscall wrapper code depends on this - because it doesn't explicitly save the other registers which hold - relevant values. */ - .text - - .hidden __pthread_enable_asynccancel -ENTRY(__pthread_enable_asynccancel) - movl %fs:CANCELHANDLING, %eax -2: movl %eax, %r11d - orl $TCB_CANCELTYPE_BITMASK, %r11d - cmpl %eax, %r11d - je 1f - - lock - cmpxchgl %r11d, %fs:CANCELHANDLING - jnz 2b - - andl $(TCB_CANCELSTATE_BITMASK|TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK|TCB_EXITING_BITMASK|TCB_CANCEL_RESTMASK|TCB_TERMINATED_BITMASK), %r11d - cmpl $(TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK), %r11d - je 3f - -1: ret - -3: subq $8, %rsp - cfi_adjust_cfa_offset(8) - LP_OP(mov) $TCB_PTHREAD_CANCELED, %fs:RESULT - lock - orl $TCB_EXITING_BITMASK, %fs:CANCELHANDLING - mov %fs:CLEANUP_JMP_BUF, %RDI_LP - call PTHREAD_UNWIND - hlt -END(__pthread_enable_asynccancel) - - - .hidden __pthread_disable_asynccancel -ENTRY(__pthread_disable_asynccancel) - testl $TCB_CANCELTYPE_BITMASK, %edi - jnz 1f - - movl %fs:CANCELHANDLING, %eax -2: movl %eax, %r11d - andl $~TCB_CANCELTYPE_BITMASK, %r11d - lock - cmpxchgl %r11d, %fs:CANCELHANDLING - jnz 2b - - movl %r11d, %eax -3: andl $(TCB_CANCELING_BITMASK|TCB_CANCELED_BITMASK), %eax - cmpl $TCB_CANCELING_BITMASK, %eax - je 4f -1: ret - - /* Performance doesn't matter in this loop. We will - delay until the thread is canceled. And we will unlikely - enter the loop twice. */ -4: mov %fs:0, %RDI_LP - movl $__NR_futex, %eax - xorq %r10, %r10 - addq $CANCELHANDLING, %rdi - LOAD_PRIVATE_FUTEX_WAIT (%esi) - syscall - movl %fs:CANCELHANDLING, %eax - jmp 3b -END(__pthread_disable_asynccancel) diff --git a/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S b/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S deleted file mode 100644 index cf8da66..0000000 --- a/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S +++ /dev/null @@ -1,21 +0,0 @@ -/* Copyright (C) 2009-2019 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Ulrich Drepper <drepper@redhat.com>, 2009. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#define __pthread_enable_asynccancel __libc_enable_asynccancel -#define __pthread_disable_asynccancel __libc_disable_asynccancel -#include "cancellation.S" diff --git a/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S b/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S deleted file mode 100644 index e7dcc61..0000000 --- a/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S +++ /dev/null @@ -1,21 +0,0 @@ -/* Copyright (C) 2009-2019 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Ulrich Drepper <drepper@redhat.com>, 2009. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#define __pthread_enable_asynccancel __librt_enable_asynccancel -#define __pthread_disable_asynccancel __librt_disable_asynccancel -#include "cancellation.S" diff --git a/sysdeps/unix/sysv/linux/x86_64/syscall_cancel.S b/sysdeps/unix/sysv/linux/x86_64/syscall_cancel.S new file mode 100644 index 0000000..35d4733 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/syscall_cancel.S @@ -0,0 +1,59 @@ +/* Cancellable syscall wrapper - x86_64 version. + Copyright (C) 2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + +/* long int [rax] __syscall_cancel_arch (volatile int *cancelhandling [%rdi], + __syscall_arg_t nr [%rsi], + __syscall_arg_t arg1 [%rdx], + __syscall_arg_t arg2 [%rcx], + __syscall_arg_t arg3 [%r8], + __syscall_arg_t arg4 [%r9], + __syscall_arg_t arg5 [SP+8], + __syscall_arg_t arg6 [SP+16]) */ + +ENTRY (__syscall_cancel_arch) + + .globl __syscall_cancel_arch_start +__syscall_cancel_arch_start: + + /* if (*cancelhandling & CANCELED_BITMASK) + __syscall_do_cancel() */ + mov (%rdi),%eax + testb $TCB_CANCELED_BITMASK, (%rdi) + jne __syscall_do_cancel + + /* Issue a 6 argument syscall, the nr [%rax] being the syscall + number. */ + mov %rdi,%r11 + mov %rsi,%rax + mov %rdx,%rdi + mov %rcx,%rsi + mov %r8,%rdx + mov %r9,%r10 + mov 8(%rsp),%r8 + mov 16(%rsp),%r9 + mov %r11,8(%rsp) + syscall + + .globl __syscall_cancel_arch_end +__syscall_cancel_arch_end: + ret + +END (__syscall_cancel_arch) +libc_hidden_def (__syscall_cancel_arch) diff --git a/sysdeps/x86_64/nptl/tcb-offsets.sym b/sysdeps/x86_64/nptl/tcb-offsets.sym index ae80347..699f6fa 100644 --- a/sysdeps/x86_64/nptl/tcb-offsets.sym +++ b/sysdeps/x86_64/nptl/tcb-offsets.sym @@ -15,12 +15,5 @@ VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache) FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1) SSP_BASE_OFFSET offsetof (tcbhead_t, ssp_base) --- Not strictly offsets, but these values are also used in the TCB. -TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK -TCB_CANCELTYPE_BITMASK CANCELTYPE_BITMASK -TCB_CANCELING_BITMASK CANCELING_BITMASK -TCB_CANCELED_BITMASK CANCELED_BITMASK -TCB_EXITING_BITMASK EXITING_BITMASK -TCB_CANCEL_RESTMASK CANCEL_RESTMASK -TCB_TERMINATED_BITMASK TERMINATED_BITMASK -TCB_PTHREAD_CANCELED PTHREAD_CANCELED +-- Not strictly offsets, used on syscall_cancel.S +TCB_CANCELED_BITMASK CANCELED_BITMASK
next reply other threads:[~2019-10-17 13:57 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-10-17 13:57 Adhemerval Zanella [this message] -- strict thread matches above, loose matches on Subject: below -- 2020-04-07 14:03 [glibc/azanella/bz12683] nptl: x86_64: Fix Race conditions in pthread cancellation [BZ#12683] Adhemerval Zanella 2020-04-03 20:23 Adhemerval Zanella 2019-08-19 20:35 [glibc/azanella/bz12683] nptl: x86_64: Fix Race conditions in pthread cancellation (BZ#12683) Adhemerval Zanella
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