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From: Eugene Syromyatnikov <evgsyr-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Cc: linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH] prctl.2: Add note regarding the size of the output user space buffer for PR_GET_TID_ADDRESS operation on x32/n32
Date: Mon, 12 Dec 2016 06:54:41 +0300	[thread overview]
Message-ID: <20161212035441.GA29133@obsidian> (raw)

---
 man2/prctl.2 | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/man2/prctl.2 b/man2/prctl.2
index 5f84bb7..39b3e9a 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2
@@ -988,7 +988,10 @@ flag, in the location pointed to by
 .IR "(int\ **)\ arg2" .
 This feature is available only if the kernel is built with the
 .BR CONFIG_CHECKPOINT_RESTORE
-option enabled.
+option enabled. Note that since the prctl() syscall does not have compat
+implementation for AMD64 x32 and MIPS n32 ABIs, and the kernel writes out
+pointer of kernel's pointer size, this operation expects a user space buffer
+of 8 (not 4) bytes on these ABIs.
 .TP
 .BR PR_SET_TIMERSLACK " (since Linux 2.6.28)"
 .\" See https://lwn.net/Articles/369549/
-- 
2.10.2

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             reply	other threads:[~2016-12-12  3:54 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-12  3:54 Eugene Syromyatnikov [this message]
2016-12-12  6:21 ` [PATCH] prctl.2: Add note regarding the size of the output user space buffer for PR_GET_TID_ADDRESS operation on x32/n32 Michael Kerrisk (man-pages)
2016-12-12  6:22 ` Michael Kerrisk (man-pages)

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