Date: Sun, 29 Jul 2018 19:16:58 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 230162] mprotect(2): error converting size argument in 32-bit emulation Message-ID: <bug-230162-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230162 Bug ID: 230162 Summary: mprotect(2): error converting size argument in 32-bit emulation Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: asomers@FreeBSD.org The lib/libc/sys/mprotect_test:mprotect_err test fails when run under 32-bit emulation. Examining the problem with dtrace, it looks like there's a casting error; the 32-bit syscall's len argument winds up in the high half of kern_mprotect's size argument. I don't see that behavior when I dtrace msgsnd, another syscall with a size_t argument. Here's an example of the problem. Notice how len=0x1 in syscall:freebsd32_mprotect, but 0x100000000 in fbt:kern_mprotect $ sudo dtrace -i 'fbt:kernel:kern_mprotect:entry {printf("addr0=%#lx, size=%#lx", args[1], args[2]);}' -i 'syscall:freebsd32:freebsd32_mprotect:entry {printf("addr=%p len=%#lx", args[0], args[1]);}' -i 'fbt:kernel:vm_map_protect:entry {printf("size ~= %#lx", args[2] - args[1]);}' dtrace: description 'fbt:kernel:kern_mprotect:entry ' matched 1 probe dtrace: description 'syscall:freebsd32:freebsd32_mprotect:entry ' matched 1 probe dtrace: description 'fbt:kernel:vm_map_protect:entry ' matched 1 probe CPU ID FUNCTION:NAME 2 61769 freebsd32_mprotect:entry addr=0 len=0 2 28572 kern_mprotect:entry addr0=0, size=0 2 47917 vm_map_protect:entry size ~= 0 3 61769 freebsd32_mprotect:entry addr=ffffffff len=0x1 3 28572 kern_mprotect:entry addr0=0xfffff000, size=0x100000000 3 47917 vm_map_protect:entry size ~= 0x1000 And in another terminal, in a 32-bit chroot, run # kyua debug mprotect_test:mprotect_err mprotect_test:mprotect_err -> failed: /usr/home/somers/freebsd/base/head/contrib/netbsd-tests/lib/libc/sys/t_mprotect.c:158: mprotect((char *)-1, 1, PROT_READ) != 0 not met -- You are receiving this mail because: You are the assignee for the bug.
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