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62 lines
2.6 KiB
62 lines
2.6 KiB
commit b3a810d0d3d5c6ce7ddfb61321cd7971808ca703 |
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Author: Stefan Liebler <stli@linux.vnet.ibm.com> |
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Date: Tue May 17 10:45:48 2016 +0200 |
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Fix tst-cancel17/tst-cancelx17, which sometimes segfaults while exiting. |
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The testcase tst-cancel[x]17 ends sometimes with a segmentation fault. |
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This happens in one of 10000 cases. Then the real testcase has already |
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exited with success and returned from do_test(). The segmentation fault |
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occurs after returning from main in _dl_fini(). |
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In those cases, the aio_read(&a) was not canceled because the read |
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request was already in progress. In the meanwhile aio_write(ap) wrote |
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something to the pipe and the read request is able to read the |
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requested byte. |
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The read request hasn't finished before returning from do_test(). |
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After it finishes, it writes the return value and error code from the |
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read syscall to the struct aiocb a, which lies on the stack of do_test. |
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The stack of the subsequent function call of _dl_fini or _dl_sort_fini, |
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which is inlined in _dl_fini is corrupted. |
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In case of S390, it reads a zero and decrements it by 1: |
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unsigned int k = nmaps - 1; |
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struct link_map **runp = maps[k]->l_initfini; |
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The load from unmapped memory leads to the segmentation fault. |
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The stack corruption also happens on other architectures. |
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I saw them e.g. on x86 and ppc, too. |
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This patch adds an aio_suspend call to ensure, that the read request |
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is finished before returning from do_test(). |
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ChangeLog: |
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* nptl/tst-cancel17.c (do_test): Wait for finishing aio_read(&a). |
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diff --git a/nptl/tst-cancel17.c b/nptl/tst-cancel17.c |
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index fb89292..eedd28e 100644 |
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--- a/nptl/tst-cancel17.c |
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+++ b/nptl/tst-cancel17.c |
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@@ -333,6 +333,22 @@ do_test (void) |
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puts ("early cancellation succeeded"); |
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+ if (ap == &a2) |
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+ { |
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+ /* The aio_read(&a) was not canceled because the read request was |
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+ already in progress. In the meanwhile aio_write(ap) wrote something |
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+ to the pipe and the read request either has already been finished or |
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+ is able to read the requested byte. |
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+ Wait for the read request before returning from this function because |
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+ the return value and error code from the read syscall will be written |
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+ to the struct aiocb a, which lies on the stack of this function. |
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+ Otherwise the stack from subsequent function calls - e.g. _dl_fini - |
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+ will be corrupted, which can lead to undefined behaviour like a |
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+ segmentation fault. */ |
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+ const struct aiocb *l[1] = { &a }; |
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+ TEMP_FAILURE_RETRY (aio_suspend(l, 1, NULL)); |
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+ } |
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+ |
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return 0; |
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} |
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