linux-kernel - [PATCH 7/3] signal: Deliver all of the perf_data in si

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Date:   Fri, 30 Apr 2021 18:43:53 -0500
From:   ebiederm@...ssion.com (Eric W. Biederman)
To:     Marco Elver <elver@...gle.com>
Cc:     Arnd Bergmann <arnd@...db.de>, Florian Weimer <fweimer@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Collingbourne <pcc@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        sparclinux <sparclinux@...r.kernel.org>,
        linux-arch <linux-arch@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux API <linux-api@...r.kernel.org>,
        kasan-dev <kasan-dev@...glegroups.com>
Subject: [PATCH 7/3] signal: Deliver all of the perf_data in si_perf


Don't abuse si_errno and deliver all of the perf data in si_perf.

Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
 fs/signalfd.c                      |  3 ++-
 include/linux/compat.h             |  5 ++++-
 include/uapi/asm-generic/siginfo.h |  5 ++++-
 include/uapi/linux/signalfd.h      |  4 ++--
 kernel/signal.c                    | 18 +++++++++++-------
 5 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/fs/signalfd.c b/fs/signalfd.c
index 83130244f653..9686af56f073 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -134,7 +134,8 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
 		break;
 	case SIL_FAULT_PERF_EVENT:
 		new.ssi_addr = (long) kinfo->si_addr;
-		new.ssi_perf = kinfo->si_perf;
+		new.ssi_perf_type = kinfo->si_perf.type;
+		new.ssi_perf_data = kinfo->si_perf.data;
 		break;
 	case SIL_CHLD:
 		new.ssi_pid    = kinfo->si_pid;
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 24462ed63af4..0726f9b3a57c 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -235,7 +235,10 @@ typedef struct compat_siginfo {
 					u32 _pkey;
 				} _addr_pkey;
 				/* used when si_code=TRAP_PERF */
-				compat_ulong_t _perf;
+				struct {
+					compat_ulong_t data;
+					u32 type;
+				} _perf;
 			};
 		} _sigfault;
 
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 2abdf1d19aad..19b6310021a3 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -90,7 +90,10 @@ union __sifields {
 				__u32 _pkey;
 			} _addr_pkey;
 			/* used when si_code=TRAP_PERF */
-			unsigned long _perf;
+			struct {
+				unsigned long data;
+				u32 type;
+			} _perf;
 		};
 	} _sigfault;
 
diff --git a/include/uapi/linux/signalfd.h b/include/uapi/linux/signalfd.h
index 7e333042c7e3..e78dddf433fc 100644
--- a/include/uapi/linux/signalfd.h
+++ b/include/uapi/linux/signalfd.h
@@ -39,8 +39,8 @@ struct signalfd_siginfo {
 	__s32 ssi_syscall;
 	__u64 ssi_call_addr;
 	__u32 ssi_arch;
-	__u32 __pad3;
-	__u64 ssi_perf;
+	__u32 ssi_perf_type;
+	__u64 ssi_perf_data;
 
 	/*
 	 * Pad strcture to 128 bytes. Remember to update the
diff --git a/kernel/signal.c b/kernel/signal.c
index 5b1ad7f080ab..cb3574b7319c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1758,11 +1758,13 @@ int force_sig_perf(void __user *pending_addr, u32 type, u64 sig_data)
 	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
-	info.si_signo = SIGTRAP;
-	info.si_errno = type;
-	info.si_code  = TRAP_PERF;
-	info.si_addr  = pending_addr;
-	info.si_perf  = sig_data;
+	info.si_signo     = SIGTRAP;
+	info.si_errno     = 0;
+	info.si_code      = TRAP_PERF;
+	info.si_addr      = pending_addr;
+	info.si_perf.data = sig_data;
+	info.si_perf.type = type;
+
 	return force_sig_info(&info);
 }
 
@@ -3379,7 +3381,8 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
 		break;
 	case SIL_FAULT_PERF_EVENT:
 		to->si_addr = ptr_to_compat(from->si_addr);
-		to->si_perf = from->si_perf;
+		to->si_perf.data = from->si_perf.data;
+		to->si_perf.type = from->si_perf.type;
 		break;
 	case SIL_CHLD:
 		to->si_pid = from->si_pid;
@@ -3455,7 +3458,8 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
 		break;
 	case SIL_FAULT_PERF_EVENT:
 		to->si_addr = compat_ptr(from->si_addr);
-		to->si_perf = from->si_perf;
+		to->si_perf.data = from->si_perf.data;
+		to->si_perf.type = from->si_perf.type;
 		break;
 	case SIL_CHLD:
 		to->si_pid    = from->si_pid;
-- 
2.30.1