Re: [PATCH 2/4] HWPOISON: Copy si_addr_lsb to user

[Hidetoshi Seto]

(2010/10/07 5:48), Andi Kleen wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> 
> The original hwpoison code added a new siginfo field si_addr_lsb to
> pass the granuality of the fault address to user space. Unfortunately
> this field was never copied to user space. Fix this here.
> 
> I added explicit checks for the MCEERR codes to avoid having
> to patch all potential callers to initialize the field.

Now QEMU uses signalfd to catch the SIGBUS delivered to the
main thread, so I think similar fix to copy lsb to user is
required for signalfd too. 


Thanks,
H.Seto

=====

From: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
Subject: [PATCH] signalfd: add support addr_lsb

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
---
 fs/signalfd.c            |   10 ++++++++++
 include/linux/signalfd.h |    3 ++-
 2 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/fs/signalfd.c b/fs/signalfd.c
index 1c5a6ad..3e28173 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -99,6 +99,16 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
 #ifdef __ARCH_SI_TRAPNO
 		err |= __put_user(kinfo->si_trapno, &uinfo->ssi_trapno);
 #endif
+#ifdef BUS_MCEERR_AO
+		/* 
+		 * Other callers might not initialize the si_lsb field,
+		 * so check explicitely for the right codes here.
+		 */
+		if (kinfo->si_code == BUS_MCEERR_AR ||
+		    kinfo->si_code == BUS_MCEERR_AO)
+			err |= __put_user((short) kinfo->si_addr_lsb,
+					  &uinfo->ssi_addr_lsb);
+#endif
 		break;
 	case __SI_CHLD:
 		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
diff --git a/include/linux/signalfd.h b/include/linux/signalfd.h
index b363b91..3ff4961 100644
--- a/include/linux/signalfd.h
+++ b/include/linux/signalfd.h
@@ -33,6 +33,7 @@ struct signalfd_siginfo {
 	__u64 ssi_utime;
 	__u64 ssi_stime;
 	__u64 ssi_addr;
+	__u16 ssi_addr_lsb;
 
 	/*
 	 * Pad strcture to 128 bytes. Remember to update the
@@ -43,7 +44,7 @@ struct signalfd_siginfo {
 	 * comes out of a read(2) and we really don't want to have
 	 * a compat on read(2).
 	 */
-	__u8 __pad[48];
+	__u8 __pad[46];
 };
 
 
-- 
1.7.3.1

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