Date: Sun, 29 May 2016 20:45:28 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 209842] backtrace(3) function can return negative Message-ID: <bug-209842-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D209842 Bug ID: 209842 Summary: backtrace(3) function can return negative Product: Base System Version: 10.3-RELEASE Hardware: arm OS: Any Status: New Severity: Affects Only Me Priority: --- Component: misc Assignee: freebsd-bugs@FreeBSD.org Reporter: phk@FreeBSD.org The backtrace(3) function returns size_t which is unsigned: size_t backtrace(void **addrlist, size_t len); And is documentet as returning: RETURN VALUES The backtrace() function returns the number of elements that were fill= ed in the backtrace. [...] The implementation in contrib/libexecinfo/unwind.c clearly knows that the return value can be all-ones: if (ctx.n !=3D (size_t)~0 && ctx.n > 0) ctx.arr[--ctx.n] =3D NULL; /* Skip frame below __sta= rt */ return ctx.n; This happens on a BeagleBoneBlack running 10.3-STABLE FreeBSD 10.3-STABLE #0 r300092 I am not sure what the proper fix is here, nor for that matter what the pro= blem might be that causes it to return the all-ones value in the first place. But at the very least ctx.n should be slammed to zero before returning it, = so the code calling backtrace(3) doesn't run off the end of the world. --=20 You are receiving this mail because: You are the assignee for the bug.=
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