Re: [PATCH v3 11/12] signal: Deliver all of the siginfo perf data in _perf
From: Marco Elver <elver@google.com>
Date: 2021-05-05 17:57:31
Also in:
linux-api, lkml, sparclinux
On Wed, 5 May 2021 at 16:11, Eric W. Beiderman [off-list ref] wrote:
From: "Eric W. Biederman" <redacted> Don't abuse si_errno and deliver all of the perf data in _perf member of siginfo_t. The data field in the perf data structures in a u64 to allow a pointer to be encoded without needed to implement a 32bit and 64bit version of the same structure. There already exists a 32bit and 64bit versions siginfo_t, and the 32bit version can not include a 64bit member as it only has 32bit alignment. So unsigned long is used in siginfo_t instead of a u64 as unsigned long can encode a pointer on all architectures linux supports.
Since there is no functional change (we already had the unsigned long here), the explanation made me think there was a change in that area (but there wasn't). (Can leave as-is, but a "Note: " or similar if you deem it appropriate.)
v1: https://lkml.kernel.org/r/m11rarqqx2.fsf_-_@fess.ebiederm.org v2: https://lkml.kernel.org/r/20210503203814.25487-10-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <redacted>
Reviewed-by: Marco Elver <elver@google.com> Thank you!
quoted hunk ↗ jump to hunk
--- arch/arm/kernel/signal.c | 3 ++- arch/arm64/kernel/signal.c | 3 ++- arch/arm64/kernel/signal32.c | 3 ++- arch/sparc/kernel/signal32.c | 3 ++- arch/sparc/kernel/signal_64.c | 3 ++- arch/x86/kernel/signal_compat.c | 6 ++++-- fs/signalfd.c | 3 ++- include/linux/compat.h | 5 ++++- include/uapi/asm-generic/siginfo.h | 8 +++++-- include/uapi/linux/signalfd.h | 4 ++-- kernel/signal.c | 21 ++++++++++++------- .../selftests/perf_events/sigtrap_threads.c | 12 +++++------ 12 files changed, 47 insertions(+), 27 deletions(-)diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 643bcb0f091b..f3800c0f428b 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c@@ -757,7 +757,8 @@ static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x10); static_assert(offsetof(siginfo_t, si_lower) == 0x14); static_assert(offsetof(siginfo_t, si_upper) == 0x18); static_assert(offsetof(siginfo_t, si_pkey) == 0x14); -static_assert(offsetof(siginfo_t, si_perf) == 0x10); +static_assert(offsetof(siginfo_t, si_perf_data) == 0x10); +static_assert(offsetof(siginfo_t, si_perf_type) == 0x14); static_assert(offsetof(siginfo_t, si_band) == 0x0c); static_assert(offsetof(siginfo_t, si_fd) == 0x10); static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c);diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index ad4bd27fc044..b3978b468bd4 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c@@ -1005,7 +1005,8 @@ static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x18); static_assert(offsetof(siginfo_t, si_lower) == 0x20); static_assert(offsetof(siginfo_t, si_upper) == 0x28); static_assert(offsetof(siginfo_t, si_pkey) == 0x20); -static_assert(offsetof(siginfo_t, si_perf) == 0x18); +static_assert(offsetof(siginfo_t, si_perf_data) == 0x18); +static_assert(offsetof(siginfo_t, si_perf_type) == 0x20); static_assert(offsetof(siginfo_t, si_band) == 0x10); static_assert(offsetof(siginfo_t, si_fd) == 0x18); static_assert(offsetof(siginfo_t, si_call_addr) == 0x10);diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index ee6c7484e130..d3be01c46bec 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c@@ -489,7 +489,8 @@ static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x10); static_assert(offsetof(compat_siginfo_t, si_lower) == 0x14); static_assert(offsetof(compat_siginfo_t, si_upper) == 0x18); static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x14); -static_assert(offsetof(compat_siginfo_t, si_perf) == 0x10); +static_assert(offsetof(compat_siginfo_t, si_perf_data) == 0x10); +static_assert(offsetof(compat_siginfo_t, si_perf_type) == 0x14); static_assert(offsetof(compat_siginfo_t, si_band) == 0x0c); static_assert(offsetof(compat_siginfo_t, si_fd) == 0x10); static_assert(offsetof(compat_siginfo_t, si_call_addr) == 0x0c);diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c index 5573722e34ad..4276b9e003ca 100644 --- a/arch/sparc/kernel/signal32.c +++ b/arch/sparc/kernel/signal32.c@@ -778,6 +778,7 @@ static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x10); static_assert(offsetof(compat_siginfo_t, si_lower) == 0x14); static_assert(offsetof(compat_siginfo_t, si_upper) == 0x18); static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x14); -static_assert(offsetof(compat_siginfo_t, si_perf) == 0x10); +static_assert(offsetof(compat_siginfo_t, si_perf_data) == 0x10); +static_assert(offsetof(compat_siginfo_t, si_perf_type) == 0x14); static_assert(offsetof(compat_siginfo_t, si_band) == 0x0c); static_assert(offsetof(compat_siginfo_t, si_fd) == 0x10);diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c index a69a78984c36..cea23cf95600 100644 --- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c@@ -588,6 +588,7 @@ static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x18); static_assert(offsetof(siginfo_t, si_lower) == 0x20); static_assert(offsetof(siginfo_t, si_upper) == 0x28); static_assert(offsetof(siginfo_t, si_pkey) == 0x20); -static_assert(offsetof(siginfo_t, si_perf) == 0x18); +static_assert(offsetof(siginfo_t, si_perf_data) == 0x18); +static_assert(offsetof(siginfo_t, si_perf_type) == 0x20); static_assert(offsetof(siginfo_t, si_band) == 0x10); static_assert(offsetof(siginfo_t, si_fd) == 0x14);diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c index c9601f092a1e..b52407c56000 100644 --- a/arch/x86/kernel/signal_compat.c +++ b/arch/x86/kernel/signal_compat.c@@ -147,8 +147,10 @@ static inline void signal_compat_build_tests(void) BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x20); BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pkey) != 0x14); - BUILD_BUG_ON(offsetof(siginfo_t, si_perf) != 0x18); - BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf) != 0x10); + BUILD_BUG_ON(offsetof(siginfo_t, si_perf_data) != 0x18); + BUILD_BUG_ON(offsetof(siginfo_t, si_perf_type) != 0x20); + BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf_data) != 0x10); + BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf_type) != 0x14); CHECK_CSI_OFFSET(_sigpoll); CHECK_CSI_SIZE (_sigpoll, 2*sizeof(int));diff --git a/fs/signalfd.c b/fs/signalfd.c index 83130244f653..335ad39f3900 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 6af7bef15e94..a27fffaae121 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h@@ -236,7 +236,10 @@ 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 3503282021aa..3ba180f550d7 100644 --- a/include/uapi/asm-generic/siginfo.h +++ b/include/uapi/asm-generic/siginfo.h@@ -96,7 +96,10 @@ union __sifields { __u32 _pkey; } _addr_pkey; /* used when si_code=TRAP_PERF */ - unsigned long _perf; + struct { + unsigned long _data; + __u32 _type; + } _perf; }; } _sigfault;@@ -159,7 +162,8 @@ typedef struct siginfo { #define si_lower _sifields._sigfault._addr_bnd._lower #define si_upper _sifields._sigfault._addr_bnd._upper #define si_pkey _sifields._sigfault._addr_pkey._pkey -#define si_perf _sifields._sigfault._perf +#define si_perf_data _sifields._sigfault._perf._data +#define si_perf_type _sifields._sigfault._perf._type #define si_band _sifields._sigpoll._band #define si_fd _sifields._sigpoll._fd #define si_call_addr _sifields._sigsys._call_addrdiff --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 thediff --git a/kernel/signal.c b/kernel/signal.c index 49560ceac048..7fec9d1c5b11 100644 --- a/kernel/signal.c +++ b/kernel/signal.c@@ -1758,11 +1758,13 @@ int force_sig_perf(void __user *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 = addr; - info.si_perf = sig_data; + info.si_signo = SIGTRAP; + info.si_errno = 0; + info.si_code = TRAP_PERF; + info.si_addr = addr; + info.si_perf_data = sig_data; + info.si_perf_type = type; + return force_sig_info(&info); }@@ -3380,7 +3382,8 @@ 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;@@ -3456,7 +3459,8 @@ 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;@@ -4639,7 +4643,8 @@ static inline void siginfo_buildtime_checks(void) CHECK_OFFSET(si_lower); CHECK_OFFSET(si_upper); CHECK_OFFSET(si_pkey); - CHECK_OFFSET(si_perf); + CHECK_OFFSET(si_perf_data); + CHECK_OFFSET(si_perf_type); /* sigpoll */ CHECK_OFFSET(si_band);diff --git a/tools/testing/selftests/perf_events/sigtrap_threads.c b/tools/testing/selftests/perf_events/sigtrap_threads.c index 78ddf5e11625..fde123066a8c 100644 --- a/tools/testing/selftests/perf_events/sigtrap_threads.c +++ b/tools/testing/selftests/perf_events/sigtrap_threads.c@@ -164,8 +164,8 @@ TEST_F(sigtrap_threads, enable_event) EXPECT_EQ(ctx.signal_count, NUM_THREADS); EXPECT_EQ(ctx.tids_want_signal, 0); EXPECT_EQ(ctx.first_siginfo.si_addr, &ctx.iterate_on); - EXPECT_EQ(ctx.first_siginfo.si_errno, PERF_TYPE_BREAKPOINT); - EXPECT_EQ(ctx.first_siginfo.si_perf, TEST_SIG_DATA(&ctx.iterate_on)); + EXPECT_EQ(ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT); + EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on)); /* Check enabled for parent. */ ctx.iterate_on = 0;@@ -183,8 +183,8 @@ TEST_F(sigtrap_threads, modify_and_enable_event) EXPECT_EQ(ctx.signal_count, NUM_THREADS); EXPECT_EQ(ctx.tids_want_signal, 0); EXPECT_EQ(ctx.first_siginfo.si_addr, &ctx.iterate_on); - EXPECT_EQ(ctx.first_siginfo.si_errno, PERF_TYPE_BREAKPOINT); - EXPECT_EQ(ctx.first_siginfo.si_perf, TEST_SIG_DATA(&ctx.iterate_on)); + EXPECT_EQ(ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT); + EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on)); /* Check enabled for parent. */ ctx.iterate_on = 0;@@ -203,8 +203,8 @@ TEST_F(sigtrap_threads, signal_stress) EXPECT_EQ(ctx.signal_count, NUM_THREADS * ctx.iterate_on); EXPECT_EQ(ctx.tids_want_signal, 0); EXPECT_EQ(ctx.first_siginfo.si_addr, &ctx.iterate_on); - EXPECT_EQ(ctx.first_siginfo.si_errno, PERF_TYPE_BREAKPOINT); - EXPECT_EQ(ctx.first_siginfo.si_perf, TEST_SIG_DATA(&ctx.iterate_on)); + EXPECT_EQ(ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT); + EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on)); } TEST_HARNESS_MAIN --2.30.1