----- On Mar 3, 2017, at 6:43 PM, Trent Piepho [email protected] wrote:
Hi Trent, What lttng-modules branch is this for ? > Patch to fix recv() syscall missing in ARM syscall list. This was probably missing because the current ARM syscall instrumentation was generated from a 3.4.25 kernel that was missing SYSCALL macro description of those system calls. The proper route would be to regenerate the system call table by running a more recent kernel and following instrumentation/syscalls/README from lttng-modules. Those changes will go into master, but those are not fixes per se: they increase the instrumentation coverage. So those are not strictly considered as fixes, and should not be backported to stable lttng-modules versions. > > Patch from lttng mailing list that fixes kernel timestamps being off > by about ~2 seconds on 32-bit systems. Additional patch to fix > compilation bug on non-X86 introduced by previous patch. Why are you re-posting an old version of own patch which now merged into master, stable-2.9 and stable-2.8 branches of lttng-modules ? I don't understand the purpose of this email. Thanks, Mathieu > > Signed-off-by: Trent Piepho <[email protected]> > --- > ...trumentation-Add-recv-to-ARM-syscall-tabl.patch | 54 ++++++ > ...0002-Fix-nmi-safe-clock-on-32-bit-systems.patch | 188 +++++++++++++++++++++ > ...Fix-trace-clock-wrapper-to-compile-on-ARM.patch | 32 ++++ > 3 files changed, 274 insertions(+) > create mode 100644 > package/lttng-modules/0001-syscall-instrumentation-Add-recv-to-ARM-syscall-tabl.patch > create mode 100644 > package/lttng-modules/0002-Fix-nmi-safe-clock-on-32-bit-systems.patch > create mode 100644 > package/lttng-modules/0003-Fix-trace-clock-wrapper-to-compile-on-ARM.patch > > diff --git > a/package/lttng-modules/0001-syscall-instrumentation-Add-recv-to-ARM-syscall-tabl.patch > b/package/lttng-modules/0001-syscall-instrumentation-Add-recv-to-ARM-syscall-tabl.patch > new file mode 100644 > index 0000000..f65a5d4 > --- /dev/null > +++ > b/package/lttng-modules/0001-syscall-instrumentation-Add-recv-to-ARM-syscall-tabl.patch > @@ -0,0 +1,54 @@ > +From 318aba6e68e0338656909b207a96566c54becc85 Mon Sep 17 00:00:00 2001 > +From: Trent Piepho <[email protected]> > +Date: Wed, 22 Feb 2017 12:56:08 -0800 > +Subject: [PATCH] syscall instrumentation: Add recv() to ARM syscall table > + > +This was missing for some reason. > +--- > + instrumentation/syscalls/3.4.25/arm-32-syscalls-3.4.25 | 1 + > + .../syscalls/headers/arm-32-syscalls-3.4.25_pointers.h | 10 > ++++++++++ > + 2 files changed, 11 insertions(+) > + > +diff --git a/instrumentation/syscalls/3.4.25/arm-32-syscalls-3.4.25 > b/instrumentation/syscalls/3.4.25/arm-32-syscalls-3.4.25 > +index 65c3973..c2e2429 100644 > +--- a/instrumentation/syscalls/3.4.25/arm-32-syscalls-3.4.25 > ++++ b/instrumentation/syscalls/3.4.25/arm-32-syscalls-3.4.25 > +@@ -221,6 +221,7 @@ syscall sys_getpeername nr 287 nbargs 3 types: (int, > struct > sockaddr *, int *) a > + syscall sys_socketpair nr 288 nbargs 4 types: (int, int, int, int *) args: > (family, type, protocol, usockvec) > + syscall sys_send nr 289 nbargs 4 types: (int, void *, size_t, unsigned) > args: > (fd, buff, len, flags) > + syscall sys_sendto nr 290 nbargs 6 types: (int, void *, size_t, unsigned, > struct sockaddr *, int) args: (fd, buff, len, flags, addr, addr_len) > ++syscall sys_recv nr 291 nbargs 4 types: (int, void *, size_t, unsigned int) > args: (fd, ubuf, size, flags) > + syscall sys_recvfrom nr 292 nbargs 6 types: (int, void *, size_t, unsigned, > struct sockaddr *, int *) args: (fd, ubuf, size, flags, addr, addr_len) > + syscall sys_shutdown nr 293 nbargs 2 types: (int, int) args: (fd, how) > + syscall sys_setsockopt nr 294 nbargs 5 types: (int, int, int, char *, int) > args: (fd, level, optname, optval, optlen) > +diff --git > a/instrumentation/syscalls/headers/arm-32-syscalls-3.4.25_pointers.h > b/instrumentation/syscalls/headers/arm-32-syscalls-3.4.25_pointers.h > +index 76aab1b..05aae76 100644 > +--- a/instrumentation/syscalls/headers/arm-32-syscalls-3.4.25_pointers.h > ++++ b/instrumentation/syscalls/headers/arm-32-syscalls-3.4.25_pointers.h > +@@ -1024,6 +1024,13 @@ SC_LTTNG_TRACEPOINT_EVENT(send, > + TP_FIELDS(sc_exit(ctf_integer(long, ret, ret)) > sc_inout(ctf_integer(int, fd, > fd)) sc_inout(ctf_integer(void *, buff, buff)) sc_inout(ctf_integer(size_t, > len, len)) sc_inout(ctf_integer(unsigned, flags, flags))) > + ) > + #endif > ++#ifndef OVERRIDE_32_recv > ++SC_LTTNG_TRACEPOINT_EVENT(recv, > ++ TP_PROTO(sc_exit(long ret,) int fd, void * ubuf, size_t size, unsigned > int > flags), > ++ TP_ARGS(sc_exit(ret,) fd, ubuf, size, flags), > ++ TP_FIELDS(sc_exit(ctf_integer(long, ret, ret)) > sc_inout(ctf_integer(int, fd, > fd)) sc_inout(ctf_integer(void *, ubuf, ubuf)) sc_inout(ctf_integer(size_t, > size, size)) sc_inout(ctf_integer(unsigned int, flags, flags))) > ++) > ++#endif > + #ifndef OVERRIDE_32_msgsnd > + SC_LTTNG_TRACEPOINT_EVENT(msgsnd, > + TP_PROTO(sc_exit(long ret,) int msqid, struct msgbuf * msgp, size_t > msgsz, > int msgflg), > +@@ -1762,6 +1769,9 @@ TRACE_SYSCALL_TABLE(send, send, 289, 4) > + #ifndef OVERRIDE_TABLE_32_sendto > + TRACE_SYSCALL_TABLE(sendto, sendto, 290, 6) > + #endif > ++#ifndef OVERRIDE_TABLE_32_recv > ++TRACE_SYSCALL_TABLE(recv, recv, 291, 4) > ++#endif > + #ifndef OVERRIDE_TABLE_32_recvfrom > + TRACE_SYSCALL_TABLE(recvfrom, recvfrom, 292, 6) > + #endif > +-- > +2.7.0.25.gfc10eb5.dirty > + > diff --git > a/package/lttng-modules/0002-Fix-nmi-safe-clock-on-32-bit-systems.patch > b/package/lttng-modules/0002-Fix-nmi-safe-clock-on-32-bit-systems.patch > new file mode 100644 > index 0000000..91296b8 > --- /dev/null > +++ b/package/lttng-modules/0002-Fix-nmi-safe-clock-on-32-bit-systems.patch > @@ -0,0 +1,188 @@ > +From 412bf9d51784b49c71b3ddabb3fc0e2b89a59a97 Mon Sep 17 00:00:00 2001 > +From: Mathieu Desnoyers <[email protected]> > +Date: Thu, 9 Feb 2017 20:51:29 -0500 > +Subject: [PATCH] Fix: nmi-safe clock on 32-bit systems > + > +On 32-bit systems, the current algorithm assume to have one clock read > +per 32-bit LSB overflow period, which is not guaranteed. It also has an > +issue on the first clock reads after module load, because the initial > +value for the last LSB is 0. It can cause the time to stay stuck at the > +same value for a few seconds at the beginning of the trace. > + > +It only affects 32-bit systems with kernels >= 3.17. > + > +Fix this by using the non-nmi-safe clock source on 32-bit systems, > +except for x86 systems that support double-word cmpxchg (cmpxchg8b). > + > +Signed-off-by: Mathieu Desnoyers <[email protected]> > +--- > + wrapper/trace-clock.c | 2 +- > + wrapper/trace-clock.h | 82 > +++++++++++++++++++-------------------------------- > + 2 files changed, 31 insertions(+), 53 deletions(-) > + > +diff --git a/wrapper/trace-clock.c b/wrapper/trace-clock.c > +index d9bc956..8c07942 100644 > +--- a/wrapper/trace-clock.c > ++++ b/wrapper/trace-clock.c > +@@ -24,7 +24,7 @@ > + #include <wrapper/trace-clock.h> > + > + #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)) > +-DEFINE_PER_CPU(local_t, lttng_last_tsc); > ++DEFINE_PER_CPU(struct lttng_last_timestamp, lttng_last_tsc); > + EXPORT_PER_CPU_SYMBOL(lttng_last_tsc); > + #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,16,0)) */ > + > +diff --git a/wrapper/trace-clock.h b/wrapper/trace-clock.h > +index 496fec4..7f76b1b 100644 > +--- a/wrapper/trace-clock.h > ++++ b/wrapper/trace-clock.h > +@@ -59,65 +59,43 @@ extern struct lttng_trace_clock *lttng_trace_clock; > + #define LTTNG_CLOCK_NMI_SAFE_BROKEN > + #endif > + > ++/* > ++ * We need clock values to be monotonically increasing per-cpu, which is > ++ * not strictly guaranteed by ktime_get_mono_fast_ns(). It is > ++ * straightforward to do on architectures with a 64-bit cmpxchg(), but > ++ * not so on architectures without 64-bit cmpxchg. > ++ */ > ++ > + #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0) \ > ++ && (BITS_PER_LONG == 64 || CONFIG_X86_CMPXCHG64) \ > + && !defined(LTTNG_CLOCK_NMI_SAFE_BROKEN)) > ++#define LTTNG_USE_NMI_SAFE_CLOCK > ++#endif > + > +-DECLARE_PER_CPU(local_t, lttng_last_tsc); > ++#ifdef LTTNG_USE_NMI_SAFE_CLOCK > + > +-#if (BITS_PER_LONG == 32) > + /* > +- * Fixup "src_now" using the 32 LSB from "last". We need to handle overflow > and > +- * underflow of the 32nd bit. "last" can be above, below or equal to the 32 > LSB > +- * of "src_now". > ++ * Ensure the variable is aligned on 64-bit for cmpxchg8b on 32-bit > ++ * systems. > + */ > +-static inline u64 trace_clock_fixup(u64 src_now, u32 last) > +-{ > +- u64 now; > ++struct lttng_last_timestamp { > ++ u64 v; > ++} __attribute__((aligned(sizeof(u64)))); > + > +- now = src_now & 0xFFFFFFFF00000000ULL; > +- now |= (u64) last; > +- /* Detect overflow or underflow between now and last. */ > +- if ((src_now & 0x80000000U) && !(last & 0x80000000U)) { > +- /* > +- * If 32nd bit transitions from 1 to 0, and we move forward in > +- * time from "now" to "last", then we have an overflow. > +- */ > +- if (((s32) now - (s32) last) < 0) > +- now += 0x0000000100000000ULL; > +- } else if (!(src_now & 0x80000000U) && (last & 0x80000000U)) { > +- /* > +- * If 32nd bit transitions from 0 to 1, and we move backward in > +- * time from "now" to "last", then we have an underflow. > +- */ > +- if (((s32) now - (s32) last) > 0) > +- now -= 0x0000000100000000ULL; > +- } > +- return now; > +-} > +-#else /* #if (BITS_PER_LONG == 32) */ > +-/* > +- * The fixup is pretty easy on 64-bit architectures: "last" is a 64-bit > +- * value, so we can use last directly as current time. > +- */ > +-static inline u64 trace_clock_fixup(u64 src_now, u64 last) > +-{ > +- return last; > +-} > +-#endif /* #else #if (BITS_PER_LONG == 32) */ > ++DECLARE_PER_CPU(struct lttng_last_timestamp, lttng_last_tsc); > + > + /* > + * Sometimes called with preemption enabled. Can be interrupted. > + */ > + static inline u64 trace_clock_monotonic_wrapper(void) > + { > +- u64 now; > +- unsigned long last, result; > +- local_t *last_tsc; > ++ u64 now, last, result; > ++ struct lttng_last_timestamp *last_tsc_ptr; > + > + /* Use fast nmi-safe monotonic clock provided by the Linux kernel. */ > + preempt_disable(); > +- last_tsc = lttng_this_cpu_ptr(<tng_last_tsc); > +- last = local_read(last_tsc); > ++ last_tsc_ptr = lttng_this_cpu_ptr(<tng_last_tsc); > ++ last = last_tsc_ptr->v; > + /* > + * Read "last" before "now". It is not strictly required, but it ensures > + * that an interrupt coming in won't artificially trigger a case where > +@@ -126,9 +104,9 @@ static inline u64 trace_clock_monotonic_wrapper(void) > + */ > + barrier(); > + now = ktime_get_mono_fast_ns(); > +- if (((long) now - (long) last) < 0) > +- now = trace_clock_fixup(now, last); > +- result = local_cmpxchg(last_tsc, last, (unsigned long) now); > ++ if (U64_MAX / 2 < now - last) > ++ now = last; > ++ result = cmpxchg64_local(&last_tsc_ptr->v, last, now); > + preempt_enable(); > + if (result == last) { > + /* Update done. */ > +@@ -139,11 +117,11 @@ static inline u64 trace_clock_monotonic_wrapper(void) > + * "result", since it has been sampled concurrently with our > + * time read, so it should not be far from "now". > + */ > +- return trace_clock_fixup(now, result); > ++ return result; > + } > + } > + > +-#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)) */ > ++#else /* #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ > + static inline u64 trace_clock_monotonic_wrapper(void) > + { > + ktime_t ktime; > +@@ -158,7 +136,7 @@ static inline u64 trace_clock_monotonic_wrapper(void) > + ktime = ktime_get(); > + return ktime_to_ns(ktime); > + } > +-#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)) */ > ++#endif /* #else #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ > + > + static inline u64 trace_clock_read64_monotonic(void) > + { > +@@ -185,19 +163,19 @@ static inline const char > *trace_clock_description_monotonic(void) > + return "Monotonic Clock"; > + } > + > +-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)) > ++#ifdef LTTNG_USE_NMI_SAFE_CLOCK > + static inline int get_trace_clock(void) > + { > + printk_once(KERN_WARNING "LTTng: Using mainline kernel monotonic fast > clock, > which is NMI-safe.\n"); > + return 0; > + } > +-#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)) */ > ++#else /* #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ > + static inline int get_trace_clock(void) > + { > + printk_once(KERN_WARNING "LTTng: Using mainline kernel monotonic clock. > NMIs > will not be traced.\n"); > + return 0; > + } > +-#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)) */ > ++#endif /* #else #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ > + > + static inline void put_trace_clock(void) > + { > +-- > +2.7.0.25.gfc10eb5.dirty > + > diff --git > a/package/lttng-modules/0003-Fix-trace-clock-wrapper-to-compile-on-ARM.patch > b/package/lttng-modules/0003-Fix-trace-clock-wrapper-to-compile-on-ARM.patch > new file mode 100644 > index 0000000..15708b8 > --- /dev/null > +++ > b/package/lttng-modules/0003-Fix-trace-clock-wrapper-to-compile-on-ARM.patch > @@ -0,0 +1,32 @@ > +From f69bf94310f0da5ed1791b0da4c1420b235d4b8b Mon Sep 17 00:00:00 2001 > +From: Trent Piepho <[email protected]> > +Date: Fri, 3 Mar 2017 14:25:16 -0800 > +Subject: [PATCH] Fix trace clock wrapper to compile on ARM > + > +The X86 only define isn't present. Just assume 64-bit cmpxcng works > +on all all the other architectures. > +--- > + wrapper/trace-clock.h | 6 +++++- > + 1 file changed, 5 insertions(+), 1 deletion(-) > + > +diff --git a/wrapper/trace-clock.h b/wrapper/trace-clock.h > +index 7f76b1b..066d5e6 100644 > +--- a/wrapper/trace-clock.h > ++++ b/wrapper/trace-clock.h > +@@ -66,8 +66,12 @@ extern struct lttng_trace_clock *lttng_trace_clock; > + * not so on architectures without 64-bit cmpxchg. > + */ > + > ++#if defined(ARCH_X86) && !defined(CONFIG_X86_CMPXCHG64) > ++#define LTTNG_NO_CMPXCHG64 > ++#endif > ++ > + #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0) \ > +- && (BITS_PER_LONG == 64 || CONFIG_X86_CMPXCHG64) \ > ++ && !defined(LTTNG_NO_CMPXCHG64) \ > + && !defined(LTTNG_CLOCK_NMI_SAFE_BROKEN)) > + #define LTTNG_USE_NMI_SAFE_CLOCK > + #endif > +-- > +2.7.0.25.gfc10eb5.dirty > + > -- > 2.7.0.25.gfc10eb5.dirty > > _______________________________________________ > lttng-dev mailing list > [email protected] > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
