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74 lines
2.3 KiB
74 lines
2.3 KiB
examples/ucontext-cp.c: cope with variable SIGSTKSZ |
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BZ: 1980845 |
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commit 8aac320ae8445c5434ab3be1761414a5247e5d42 |
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Author: Stefan Hajnoczi <stefanha@redhat.com> |
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Date: Tue Apr 13 16:03:19 2021 +0100 |
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examples/ucontext-cp.c: cope with variable SIGSTKSZ |
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The size of C arrays at file scope must be constant. The following |
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compiler error occurs with recent upstream glibc (2.33.9000): |
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CC ucontext-cp |
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ucontext-cp.c:31:23: error: variably modified ‘stack_buf’ at file scope |
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31 | unsigned char stack_buf[SIGSTKSZ]; |
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| ^~~~~~~~~ |
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make[1]: *** [Makefile:26: ucontext-cp] Error 1 |
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The following glibc commit changed SIGSTKSZ from a constant value to a |
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variable: |
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commit 6c57d320484988e87e446e2e60ce42816bf51d53 |
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Author: H.J. Lu <hjl.tools@gmail.com> |
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Date: Mon Feb 1 11:00:38 2021 -0800 |
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sysconf: Add _SC_MINSIGSTKSZ/_SC_SIGSTKSZ [BZ #20305] |
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... |
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+# define SIGSTKSZ sysconf (_SC_SIGSTKSZ) |
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Allocate the stack buffer explicitly to avoid declaring an array at file |
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scope. |
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Cc: H.J. Lu <hjl.tools@gmail.com> |
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> |
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Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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diff --git a/examples/ucontext-cp.c b/examples/ucontext-cp.c |
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index 0b2a6b5..ea0c934 100644 |
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--- a/examples/ucontext-cp.c |
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+++ b/examples/ucontext-cp.c |
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@@ -28,7 +28,7 @@ |
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typedef struct { |
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struct io_uring *ring; |
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- unsigned char stack_buf[SIGSTKSZ]; |
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+ unsigned char *stack_buf; |
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ucontext_t ctx_main, ctx_fnew; |
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} async_context; |
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@@ -115,8 +115,13 @@ static int setup_context(async_context *pctx, struct io_uring *ring) |
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perror("getcontext"); |
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return -1; |
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} |
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- pctx->ctx_fnew.uc_stack.ss_sp = &pctx->stack_buf; |
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- pctx->ctx_fnew.uc_stack.ss_size = sizeof(pctx->stack_buf); |
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+ pctx->stack_buf = malloc(SIGSTKSZ); |
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+ if (!pctx->stack_buf) { |
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+ perror("malloc"); |
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+ return -1; |
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+ } |
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+ pctx->ctx_fnew.uc_stack.ss_sp = pctx->stack_buf; |
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+ pctx->ctx_fnew.uc_stack.ss_size = SIGSTKSZ; |
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pctx->ctx_fnew.uc_link = &pctx->ctx_main; |
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return 0; |
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@@ -174,6 +179,7 @@ static void copy_file_wrapper(arguments_bundle *pbundle) |
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free(iov.iov_base); |
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close(pbundle->infd); |
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close(pbundle->outfd); |
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+ free(pbundle->pctx->stack_buf); |
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free(pbundle->pctx); |
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free(pbundle); |
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