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88 lines
3.8 KiB
88 lines
3.8 KiB
commit 630f4cc3aa019ede55976ea561f1a7af2f068639 |
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Author: Szabolcs Nagy <szabolcs.nagy@arm.com> |
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Date: Wed Dec 6 13:05:50 2017 +0000 |
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[BZ #22637] Fix stack guard size accounting |
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Previously if user requested S stack and G guard when creating a |
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thread, the total mapping was S and the actual available stack was |
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S - G - static_tls, which is not what the user requested. |
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This patch fixes the guard size accounting by pretending the user |
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requested S+G stack. This way all later logic works out except |
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when reporting the user requested stack size (pthread_getattr_np) |
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or when computing the minimal stack size (__pthread_get_minstack). |
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Normally this will increase thread stack allocations by one page. |
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TLS accounting is not affected, that will require a separate fix. |
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[BZ #22637] |
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* nptl/descr.h (stackblock, stackblock_size): Update comments. |
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* nptl/allocatestack.c (allocate_stack): Add guardsize to stacksize. |
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* nptl/nptl-init.c (__pthread_get_minstack): Remove guardsize from |
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stacksize. |
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* nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise. |
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Index: glibc-2.17-c758a686/nptl/allocatestack.c |
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=================================================================== |
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--- glibc-2.17-c758a686.orig/nptl/allocatestack.c |
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+++ glibc-2.17-c758a686/nptl/allocatestack.c |
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@@ -470,6 +470,10 @@ allocate_stack (const struct pthread_att |
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/* Make sure the size of the stack is enough for the guard and |
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eventually the thread descriptor. */ |
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guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1; |
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+ if (guardsize < attr->guardsize || size + guardsize < guardsize) |
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+ /* Arithmetic overflow. */ |
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+ return EINVAL; |
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+ size += guardsize; |
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if (__builtin_expect (size < ((guardsize + __static_tls_size |
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+ MINIMAL_REST_STACK + pagesize_m1) |
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& ~pagesize_m1), |
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Index: glibc-2.17-c758a686/nptl/descr.h |
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=================================================================== |
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--- glibc-2.17-c758a686.orig/nptl/descr.h |
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+++ glibc-2.17-c758a686/nptl/descr.h |
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@@ -366,9 +366,9 @@ struct pthread |
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struct _Unwind_Exception exc; |
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#endif |
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- /* If nonzero pointer to area allocated for the stack and its |
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- size. */ |
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+ /* If nonzero, pointer to the area allocated for the stack and guard. */ |
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void *stackblock; |
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+ /* Size of the stackblock area including the guard. */ |
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size_t stackblock_size; |
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/* Size of the included guard area. */ |
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size_t guardsize; |
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Index: glibc-2.17-c758a686/nptl/nptl-init.c |
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=================================================================== |
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--- glibc-2.17-c758a686.orig/nptl/nptl-init.c |
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+++ glibc-2.17-c758a686/nptl/nptl-init.c |
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@@ -500,8 +500,5 @@ strong_alias (__pthread_initialize_minim |
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size_t |
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__pthread_get_minstack (const pthread_attr_t *attr) |
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{ |
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- struct pthread_attr *iattr = (struct pthread_attr *) attr; |
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- |
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- return (GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN |
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- + iattr->guardsize); |
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+ return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN; |
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} |
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Index: glibc-2.17-c758a686/nptl/pthread_getattr_np.c |
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=================================================================== |
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--- glibc-2.17-c758a686.orig/nptl/pthread_getattr_np.c |
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+++ glibc-2.17-c758a686/nptl/pthread_getattr_np.c |
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@@ -59,8 +59,11 @@ pthread_getattr_np (thread_id, attr) |
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/* The sizes are subject to alignment. */ |
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if (__builtin_expect (thread->stackblock != NULL, 1)) |
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{ |
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- iattr->stacksize = thread->stackblock_size; |
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- iattr->stackaddr = (char *) thread->stackblock + iattr->stacksize; |
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+ /* The stack size reported to the user should not include the |
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+ guard size. */ |
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+ iattr->stacksize = thread->stackblock_size - thread->guardsize; |
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+ iattr->stackaddr = (char *) thread->stackblock |
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+ + thread->stackblock_size; |
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} |
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else |
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{
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