[Qemu-devel] [PULL 0/3] Tracing patches

[Qemu-devel] [PULL 0/3] Tracing patches

[Stefan Hajnoczi]

The following changes since commit f8c3db33a5e863291182f8862ddf81618a7c6194:

  target/sparc: Switch to do_transaction_failed() hook (2019-09-17 12:01:00 +0100)

are available in the Git repository at:

  https://github.com/stefanha/qemu.git tags/tracing-pull-request

for you to fetch changes up to 9f7ad79c16ede0da01902b18fb32929cfbd20f87:

  trace: Forbid event format ending with newline character (2019-09-18 10:20:15 +0100)

----------------------------------------------------------------
Pull request

----------------------------------------------------------------

Alexey Kardashevskiy (1):
  loader: Trace loaded images

Philippe Mathieu-Daudé (2):
  trace: Remove trailing newline in events
  trace: Forbid event format ending with newline character

 docs/devel/tracing.txt        |  2 ++
 Makefile.objs                 |  1 +
 hw/core/loader.c              |  3 +++
 hw/core/trace-events          |  2 ++
 hw/misc/trace-events          | 10 +++++-----
 hw/scsi/trace-events          |  2 +-
 hw/sd/trace-events            |  2 +-
 nbd/trace-events              |  4 ++--
 net/trace-events              |  6 +++---
 scripts/tracetool/__init__.py |  3 +++
 10 files changed, 23 insertions(+), 12 deletions(-)
 create mode 100644 hw/core/trace-events

-- 
2.21.0

[Qemu-devel] [PULL 1/3] loader: Trace loaded images

[Stefan Hajnoczi]

From: Alexey Kardashevskiy <aik@ozlabs.ru>

This adds a trace point which prints every loaded image. This includes
bios/firmware/kernel/initradmdisk/pcirom.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190613050937.124903-1-aik@ozlabs.ru>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 Makefile.objs        | 1 +
 hw/core/loader.c     | 3 +++
 hw/core/trace-events | 2 ++
 3 files changed, 6 insertions(+)
 create mode 100644 hw/core/trace-events

diff --git a/Makefile.objs b/Makefile.objs
index 6a143dcd57..abcbd89654 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -203,6 +203,7 @@ trace-events-subdirs += target/riscv
 trace-events-subdirs += target/s390x
 trace-events-subdirs += target/sparc
 trace-events-subdirs += util
+trace-events-subdirs += hw/core
 
 trace-events-files = $(SRC_PATH)/trace-events $(trace-events-subdirs:%=$(SRC_PATH)/%/trace-events)
 
diff --git a/hw/core/loader.c b/hw/core/loader.c
index 75eb56ddbb..0d60219364 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -45,6 +45,7 @@
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "qapi/error.h"
+#include "trace.h"
 #include "hw/hw.h"
 #include "disas/disas.h"
 #include "migration/vmstate.h"
@@ -1151,6 +1152,8 @@ static void rom_reset(void *unused)
          * CPU definitely fetches its instructions from the just written data.
          */
         cpu_flush_icache_range(rom->addr, rom->datasize);
+
+        trace_loader_write_rom(rom->name, rom->addr, rom->datasize, rom->isrom);
     }
 }
 
diff --git a/hw/core/trace-events b/hw/core/trace-events
new file mode 100644
index 0000000000..fe47a9c8cb
--- /dev/null
+++ b/hw/core/trace-events
@@ -0,0 +1,2 @@
+# loader.c
+loader_write_rom(const char *name, uint64_t gpa, uint64_t size, bool isrom) "%s: @0x%"PRIx64" size=0x%"PRIx64" ROM=%d"
-- 
2.21.0

[Qemu-devel] [PULL 2/3] trace: Remove trailing newline in events

[Stefan Hajnoczi]

From: Philippe Mathieu-Daudé <philmd@redhat.com>

While the tracing framework does not forbid trailing newline in
events format string, using them lead to confuse output.
It is the responsibility of the backend to properly end an event
line.

Some of our formats have trailing newlines, remove them.

[Fixed typo in commit description reported by Eric Blake
<eblake@redhat.com>
--Stefan]

Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190916095121.29506-2-philmd@redhat.com
Message-Id: <20190916095121.29506-2-philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/misc/trace-events | 10 +++++-----
 hw/scsi/trace-events |  2 +-
 hw/sd/trace-events   |  2 +-
 nbd/trace-events     |  4 ++--
 net/trace-events     |  6 +++---
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index c1ea1aa437..74276225f8 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -118,11 +118,11 @@ iotkit_secctl_ns_read(uint32_t offset, uint64_t data, unsigned size) "IoTKit Sec
 iotkit_secctl_ns_write(uint32_t offset, uint64_t data, unsigned size) "IoTKit SecCtl NS regs write: offset 0x%x data 0x%" PRIx64 " size %u"
 
 # imx6ul_ccm.c
-ccm_entry(void) "\n"
-ccm_freq(uint32_t freq) "freq = %d\n"
-ccm_clock_freq(uint32_t clock, uint32_t freq) "(Clock = %d) = %d\n"
-ccm_read_reg(const char *reg_name, uint32_t value) "reg[%s] <= 0x%" PRIx32 "\n"
-ccm_write_reg(const char *reg_name, uint32_t value) "reg[%s] => 0x%" PRIx32 "\n"
+ccm_entry(void) ""
+ccm_freq(uint32_t freq) "freq = %d"
+ccm_clock_freq(uint32_t clock, uint32_t freq) "(Clock = %d) = %d"
+ccm_read_reg(const char *reg_name, uint32_t value) "reg[%s] <= 0x%" PRIx32
+ccm_write_reg(const char *reg_name, uint32_t value) "reg[%s] => 0x%" PRIx32
 
 # iotkit-sysinfo.c
 iotkit_sysinfo_read(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysInfo read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
diff --git a/hw/scsi/trace-events b/hw/scsi/trace-events
index 452b5994e6..b0820052f8 100644
--- a/hw/scsi/trace-events
+++ b/hw/scsi/trace-events
@@ -28,7 +28,7 @@ mptsas_mmio_read(void *dev, uint32_t addr, uint32_t val) "dev %p addr 0x%08x val
 mptsas_mmio_unhandled_read(void *dev, uint32_t addr) "dev %p addr 0x%08x"
 mptsas_mmio_unhandled_write(void *dev, uint32_t addr, uint32_t val) "dev %p addr 0x%08x value 0x%x"
 mptsas_mmio_write(void *dev, uint32_t addr, uint32_t val) "dev %p addr 0x%08x value 0x%x"
-mptsas_process_message(void *dev, int msg, uint32_t ctx) "dev %p cmd %d context 0x%08x\n"
+mptsas_process_message(void *dev, int msg, uint32_t ctx) "dev %p cmd %d context 0x%08x"
 mptsas_process_scsi_io_request(void *dev, int bus, int target, int lun, uint64_t len) "dev %p dev %d:%d:%d length %"PRIu64""
 mptsas_reset(void *dev) "dev %p "
 mptsas_scsi_overflow(void *dev, uint32_t ctx, uint64_t req, uint64_t found) "dev %p context 0x%08x: %"PRIu64"/%"PRIu64""
diff --git a/hw/sd/trace-events b/hw/sd/trace-events
index 52971dc033..efcff666a2 100644
--- a/hw/sd/trace-events
+++ b/hw/sd/trace-events
@@ -4,7 +4,7 @@
 bcm2835_sdhost_read(uint64_t offset, uint64_t data, unsigned size) "offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
 bcm2835_sdhost_write(uint64_t offset, uint64_t data, unsigned size) "offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
 bcm2835_sdhost_edm_change(const char *why, uint32_t edm) "(%s) EDM now 0x%x"
-bcm2835_sdhost_update_irq(uint32_t irq) "IRQ bits 0x%x\n"
+bcm2835_sdhost_update_irq(uint32_t irq) "IRQ bits 0x%x"
 
 # core.c
 sdbus_command(const char *bus_name, uint8_t cmd, uint32_t arg) "@%s CMD%02d arg 0x%08x"
diff --git a/nbd/trace-events b/nbd/trace-events
index f6cde96790..a955918e97 100644
--- a/nbd/trace-events
+++ b/nbd/trace-events
@@ -61,8 +61,8 @@ nbd_negotiate_begin(void) "Beginning negotiation"
 nbd_negotiate_new_style_size_flags(uint64_t size, unsigned flags) "advertising size %" PRIu64 " and flags 0x%x"
 nbd_negotiate_success(void) "Negotiation succeeded"
 nbd_receive_request(uint32_t magic, uint16_t flags, uint16_t type, uint64_t from, uint32_t len) "Got request: { magic = 0x%" PRIx32 ", .flags = 0x%" PRIx16 ", .type = 0x%" PRIx16 ", from = %" PRIu64 ", len = %" PRIu32 " }"
-nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients to AIO context %p\n"
-nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p\n"
+nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients to AIO context %p"
+nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p"
 nbd_co_send_simple_reply(uint64_t handle, uint32_t error, const char *errname, int len) "Send simple reply: handle = %" PRIu64 ", error = %" PRIu32 " (%s), len = %d"
 nbd_co_send_structured_done(uint64_t handle) "Send structured reply done: handle = %" PRIu64
 nbd_co_send_structured_read(uint64_t handle, uint64_t offset, void *data, size_t size) "Send structured read data reply: handle = %" PRIu64 ", offset = %" PRIu64 ", data = %p, len = %zu"
diff --git a/net/trace-events b/net/trace-events
index ac57056497..02c13fd0ba 100644
--- a/net/trace-events
+++ b/net/trace-events
@@ -17,9 +17,9 @@ colo_compare_icmp_miscompare(const char *sta, int size) ": %s = %d"
 colo_compare_ip_info(int psize, const char *sta, const char *stb, int ssize, const char *stc, const char *std) "ppkt size = %d, ip_src = %s, ip_dst = %s, spkt size = %d, ip_src = %s, ip_dst = %s"
 colo_old_packet_check_found(int64_t old_time) "%" PRId64
 colo_compare_miscompare(void) ""
-colo_compare_tcp_info(const char *pkt, uint32_t seq, uint32_t ack, int hdlen, int pdlen, int offset, int flags) "%s: seq/ack= %u/%u hdlen= %d pdlen= %d offset= %d flags=%d\n"
+colo_compare_tcp_info(const char *pkt, uint32_t seq, uint32_t ack, int hdlen, int pdlen, int offset, int flags) "%s: seq/ack= %u/%u hdlen= %d pdlen= %d offset= %d flags=%d"
 
 # filter-rewriter.c
 colo_filter_rewriter_debug(void) ""
-colo_filter_rewriter_pkt_info(const char *func, const char *src, const char *dst, uint32_t seq, uint32_t ack, uint32_t flag) "%s: src/dst: %s/%s p: seq/ack=%u/%u  flags=0x%x\n"
-colo_filter_rewriter_conn_offset(uint32_t offset) ": offset=%u\n"
+colo_filter_rewriter_pkt_info(const char *func, const char *src, const char *dst, uint32_t seq, uint32_t ack, uint32_t flag) "%s: src/dst: %s/%s p: seq/ack=%u/%u  flags=0x%x"
+colo_filter_rewriter_conn_offset(uint32_t offset) ": offset=%u"
-- 
2.21.0

Re: [Qemu-devel] [PULL 2/3] trace: Remove trailing newline in events

[Philippe Mathieu-Daudé]

On 9/18/19 3:21 PM, Stefan Hajnoczi wrote:
> From: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
> While the tracing framework does not forbid trailing newline in
> events format string, using them lead to confuse output.
> It is the responsibility of the backend to properly end an event
> line.
> 
> Some of our formats have trailing newlines, remove them.
> 
> [Fixed typo in commit description reported by Eric Blake

Thanks for this!

> <eblake@redhat.com>
> --Stefan]
> 
> Reviewed-by: John Snow <jsnow@redhat.com>
> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Message-id: 20190916095121.29506-2-philmd@redhat.com
> Message-Id: <20190916095121.29506-2-philmd@redhat.com>

Out of curiosity, how do you end up with 2 slightly different
message-id? Using two different tools in series? (Thinking about
unifying these tools format).

> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  hw/misc/trace-events | 10 +++++-----
>  hw/scsi/trace-events |  2 +-
>  hw/sd/trace-events   |  2 +-
>  nbd/trace-events     |  4 ++--
>  net/trace-events     |  6 +++---
>  5 files changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/hw/misc/trace-events b/hw/misc/trace-events
> index c1ea1aa437..74276225f8 100644
> --- a/hw/misc/trace-events
> +++ b/hw/misc/trace-events
> @@ -118,11 +118,11 @@ iotkit_secctl_ns_read(uint32_t offset, uint64_t data, unsigned size) "IoTKit Sec
>  iotkit_secctl_ns_write(uint32_t offset, uint64_t data, unsigned size) "IoTKit SecCtl NS regs write: offset 0x%x data 0x%" PRIx64 " size %u"
>  
>  # imx6ul_ccm.c
> -ccm_entry(void) "\n"
> -ccm_freq(uint32_t freq) "freq = %d\n"
> -ccm_clock_freq(uint32_t clock, uint32_t freq) "(Clock = %d) = %d\n"
> -ccm_read_reg(const char *reg_name, uint32_t value) "reg[%s] <= 0x%" PRIx32 "\n"
> -ccm_write_reg(const char *reg_name, uint32_t value) "reg[%s] => 0x%" PRIx32 "\n"
> +ccm_entry(void) ""
> +ccm_freq(uint32_t freq) "freq = %d"
> +ccm_clock_freq(uint32_t clock, uint32_t freq) "(Clock = %d) = %d"
> +ccm_read_reg(const char *reg_name, uint32_t value) "reg[%s] <= 0x%" PRIx32
> +ccm_write_reg(const char *reg_name, uint32_t value) "reg[%s] => 0x%" PRIx32
>  
>  # iotkit-sysinfo.c
>  iotkit_sysinfo_read(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysInfo read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
> diff --git a/hw/scsi/trace-events b/hw/scsi/trace-events
> index 452b5994e6..b0820052f8 100644
> --- a/hw/scsi/trace-events
> +++ b/hw/scsi/trace-events
> @@ -28,7 +28,7 @@ mptsas_mmio_read(void *dev, uint32_t addr, uint32_t val) "dev %p addr 0x%08x val
>  mptsas_mmio_unhandled_read(void *dev, uint32_t addr) "dev %p addr 0x%08x"
>  mptsas_mmio_unhandled_write(void *dev, uint32_t addr, uint32_t val) "dev %p addr 0x%08x value 0x%x"
>  mptsas_mmio_write(void *dev, uint32_t addr, uint32_t val) "dev %p addr 0x%08x value 0x%x"
> -mptsas_process_message(void *dev, int msg, uint32_t ctx) "dev %p cmd %d context 0x%08x\n"
> +mptsas_process_message(void *dev, int msg, uint32_t ctx) "dev %p cmd %d context 0x%08x"
>  mptsas_process_scsi_io_request(void *dev, int bus, int target, int lun, uint64_t len) "dev %p dev %d:%d:%d length %"PRIu64""
>  mptsas_reset(void *dev) "dev %p "
>  mptsas_scsi_overflow(void *dev, uint32_t ctx, uint64_t req, uint64_t found) "dev %p context 0x%08x: %"PRIu64"/%"PRIu64""
> diff --git a/hw/sd/trace-events b/hw/sd/trace-events
> index 52971dc033..efcff666a2 100644
> --- a/hw/sd/trace-events
> +++ b/hw/sd/trace-events
> @@ -4,7 +4,7 @@
>  bcm2835_sdhost_read(uint64_t offset, uint64_t data, unsigned size) "offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
>  bcm2835_sdhost_write(uint64_t offset, uint64_t data, unsigned size) "offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
>  bcm2835_sdhost_edm_change(const char *why, uint32_t edm) "(%s) EDM now 0x%x"
> -bcm2835_sdhost_update_irq(uint32_t irq) "IRQ bits 0x%x\n"
> +bcm2835_sdhost_update_irq(uint32_t irq) "IRQ bits 0x%x"
>  
>  # core.c
>  sdbus_command(const char *bus_name, uint8_t cmd, uint32_t arg) "@%s CMD%02d arg 0x%08x"
> diff --git a/nbd/trace-events b/nbd/trace-events
> index f6cde96790..a955918e97 100644
> --- a/nbd/trace-events
> +++ b/nbd/trace-events
> @@ -61,8 +61,8 @@ nbd_negotiate_begin(void) "Beginning negotiation"
>  nbd_negotiate_new_style_size_flags(uint64_t size, unsigned flags) "advertising size %" PRIu64 " and flags 0x%x"
>  nbd_negotiate_success(void) "Negotiation succeeded"
>  nbd_receive_request(uint32_t magic, uint16_t flags, uint16_t type, uint64_t from, uint32_t len) "Got request: { magic = 0x%" PRIx32 ", .flags = 0x%" PRIx16 ", .type = 0x%" PRIx16 ", from = %" PRIu64 ", len = %" PRIu32 " }"
> -nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients to AIO context %p\n"
> -nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p\n"
> +nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients to AIO context %p"
> +nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p"
>  nbd_co_send_simple_reply(uint64_t handle, uint32_t error, const char *errname, int len) "Send simple reply: handle = %" PRIu64 ", error = %" PRIu32 " (%s), len = %d"
>  nbd_co_send_structured_done(uint64_t handle) "Send structured reply done: handle = %" PRIu64
>  nbd_co_send_structured_read(uint64_t handle, uint64_t offset, void *data, size_t size) "Send structured read data reply: handle = %" PRIu64 ", offset = %" PRIu64 ", data = %p, len = %zu"
> diff --git a/net/trace-events b/net/trace-events
> index ac57056497..02c13fd0ba 100644
> --- a/net/trace-events
> +++ b/net/trace-events
> @@ -17,9 +17,9 @@ colo_compare_icmp_miscompare(const char *sta, int size) ": %s = %d"
>  colo_compare_ip_info(int psize, const char *sta, const char *stb, int ssize, const char *stc, const char *std) "ppkt size = %d, ip_src = %s, ip_dst = %s, spkt size = %d, ip_src = %s, ip_dst = %s"
>  colo_old_packet_check_found(int64_t old_time) "%" PRId64
>  colo_compare_miscompare(void) ""
> -colo_compare_tcp_info(const char *pkt, uint32_t seq, uint32_t ack, int hdlen, int pdlen, int offset, int flags) "%s: seq/ack= %u/%u hdlen= %d pdlen= %d offset= %d flags=%d\n"
> +colo_compare_tcp_info(const char *pkt, uint32_t seq, uint32_t ack, int hdlen, int pdlen, int offset, int flags) "%s: seq/ack= %u/%u hdlen= %d pdlen= %d offset= %d flags=%d"
>  
>  # filter-rewriter.c
>  colo_filter_rewriter_debug(void) ""
> -colo_filter_rewriter_pkt_info(const char *func, const char *src, const char *dst, uint32_t seq, uint32_t ack, uint32_t flag) "%s: src/dst: %s/%s p: seq/ack=%u/%u  flags=0x%x\n"
> -colo_filter_rewriter_conn_offset(uint32_t offset) ": offset=%u\n"
> +colo_filter_rewriter_pkt_info(const char *func, const char *src, const char *dst, uint32_t seq, uint32_t ack, uint32_t flag) "%s: src/dst: %s/%s p: seq/ack=%u/%u  flags=0x%x"
> +colo_filter_rewriter_conn_offset(uint32_t offset) ": offset=%u"
> 

Re: [Qemu-devel] [PULL 2/3] trace: Remove trailing newline in events

[Stefan Hajnoczi]

[-- Attachment #1: Type: text/plain, Size: 614 bytes --]

On Wed, Sep 18, 2019 at 05:51:16PM +0200, Philippe Mathieu-Daudé wrote:
> On 9/18/19 3:21 PM, Stefan Hajnoczi wrote:
> > Reviewed-by: John Snow <jsnow@redhat.com>
> > Reviewed-by: Kevin Wolf <kwolf@redhat.com>
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> > Message-id: 20190916095121.29506-2-philmd@redhat.com
> > Message-Id: <20190916095121.29506-2-philmd@redhat.com>
> 
> Out of curiosity, how do you end up with 2 slightly different
> message-id? Using two different tools in series? (Thinking about
> unifying these tools format).

I'm not sure what happened here :P.

Stefan

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[Qemu-devel] [PULL 3/3] trace: Forbid event format ending with newline character

[Stefan Hajnoczi]

From: Philippe Mathieu-Daudé <philmd@redhat.com>

Event format ending with newlines confuse the trace reports.
Forbid them.

Add a check to refuse new format added with trailing newline:

  $ make
  [...]
    GEN     hw/misc/trace.h
  Traceback (most recent call last):
    File "scripts/tracetool.py", line 152, in <module>
      main(sys.argv)
    File "scripts/tracetool.py", line 143, in main
      events.extend(tracetool.read_events(fh, arg))
    File "scripts/tracetool/__init__.py", line 367, in read_events
      event = Event.build(line)
    File "scripts/tracetool/__init__.py", line 281, in build
      raise ValueError("Event format can not end with a newline character")
  ValueError: Error at hw/misc/trace-events:121: Event format can not end with a newline character

Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190916095121.29506-3-philmd@redhat.com
Message-Id: <20190916095121.29506-3-philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 docs/devel/tracing.txt        | 2 ++
 scripts/tracetool/__init__.py | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.txt
index 76e492a489..8231bbf5d1 100644
--- a/docs/devel/tracing.txt
+++ b/docs/devel/tracing.txt
@@ -112,6 +112,8 @@ Trace events should use types as follows:
 Format strings should reflect the types defined in the trace event.  Take
 special care to use PRId64 and PRIu64 for int64_t and uint64_t types,
 respectively.  This ensures portability between 32- and 64-bit platforms.
+Format strings must not end with a newline character.  It is the responsibility
+of backends to adapt line ending for proper logging.
 
 Each event declaration will start with the event name, then its arguments,
 finally a format string for pretty-printing. For example:
diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
index 6fca674936..04279fa62e 100644
--- a/scripts/tracetool/__init__.py
+++ b/scripts/tracetool/__init__.py
@@ -277,6 +277,9 @@ class Event(object):
         if fmt.find("%m") != -1 or fmt_trans.find("%m") != -1:
             raise ValueError("Event format '%m' is forbidden, pass the error "
                              "as an explicit trace argument")
+        if fmt.endswith(r'\n"'):
+            raise ValueError("Event format must not end with a newline "
+                             "character")
 
         if len(fmt_trans) > 0:
             fmt = [fmt_trans, fmt]
-- 
2.21.0

Re: [Qemu-devel] [PULL 0/3] Tracing patches

[Peter Maydell]

On Wed, 18 Sep 2019 at 14:21, Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> The following changes since commit f8c3db33a5e863291182f8862ddf81618a7c6194:
>
>   target/sparc: Switch to do_transaction_failed() hook (2019-09-17 12:01:00 +0100)
>
> are available in the Git repository at:
>
>   https://github.com/stefanha/qemu.git tags/tracing-pull-request
>
> for you to fetch changes up to 9f7ad79c16ede0da01902b18fb32929cfbd20f87:
>
>   trace: Forbid event format ending with newline character (2019-09-18 10:20:15 +0100)
>
> ----------------------------------------------------------------
> Pull request
>
> ----------------------------------------------------------------
>
> Alexey Kardashevskiy (1):
>   loader: Trace loaded images
>
> Philippe Mathieu-Daudé (2):
>   trace: Remove trailing newline in events
>   trace: Forbid event format ending with newline character


Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/4.2
for any user-visible changes.

-- PMM