From cc4b1242d7e3b42eed73881fc749944146493e4f Mon Sep 17 00:00:00 2001 From: Aurelien Jarno Date: Thu, 6 Dec 2018 20:05:34 +0100 Subject: [PATCH] vfs: fix preadv64v2 and pwritev64v2 compat syscalls with offset == -1 The preadv2 and pwritev2 syscalls are supposed to emulate the readv and writev syscalls when offset == -1. Therefore the compat code should check for offset before calling do_compat_preadv64 and do_compat_pwritev64. This is the case for the preadv2 and pwritev2 syscalls, but handling of offset == -1 is missing in their 64-bit equivalent. This patch fixes that, calling do_compat_readv and do_compat_writev when offset == -1. This fixes the following glibc tests on x32: - misc/tst-preadvwritev2 - misc/tst-preadvwritev64v2 Cc: Alexander Viro Cc: H.J. Lu Signed-off-by: Aurelien Jarno Signed-off-by: Al Viro --- fs/read_write.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/read_write.c b/fs/read_write.c index ff3c5e6f87cf..27b69b85d49f 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1238,6 +1238,9 @@ COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd, const struct compat_iovec __user *,vec, unsigned long, vlen, loff_t, pos, rwf_t, flags) { + if (pos == -1) + return do_compat_readv(fd, vec, vlen, flags); + return do_compat_preadv64(fd, vec, vlen, pos, flags); } #endif @@ -1344,6 +1347,9 @@ COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd, const struct compat_iovec __user *,vec, unsigned long, vlen, loff_t, pos, rwf_t, flags) { + if (pos == -1) + return do_compat_writev(fd, vec, vlen, flags); + return do_compat_pwritev64(fd, vec, vlen, pos, flags); } #endif