kernel.git/tools/perf/util/probe-event.c, branch linux-5.7.y

perf probe: Fix user attribute access in kprobes

2020-06-24T15:49:12Z

[ Upstream commit 9256c3031eb9beafa3957c61093104c3c75a6148 ] Issue: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' did not work before. Fix: Make: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' output equivalent to ftrace: # echo 'p:probe/do_sched_setscheduler _text+517384 pid=%r2:s32 policy=%r3:s32 sched_priority=+u0(%r4):s32' > /sys/kernel/debug/tracing/kprobe_events Other: 1. Right now, __match_glob() does not handle [u]. For now, use *u]. 2. @user attribute was introduced in commit 1e032f7cfa14 ("perf-probe: Add user memory access attribute support") Test: 1. perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' 2 ./perf script sched 305669 [000] 1614458.838675: perf_bpf_probe:func: (2904e508) pid=261614 policy=2 sched_priority=1 3. cat /sys/kernel/debug/tracing/trace <...>-309956 [006] .... 1616098.093957: 0: prio: 1 Committer testing: Before: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' param(type:sched_param) has no member sched_priority@user. Error: Failed to add events. # pahole sched_param struct sched_param { int sched_priority; /* 0 4 */ /* size: 4, cachelines: 1, members: 1 */ /* last cacheline: 4 bytes */ }; # After: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' Added new event: probe:do_sched_setscheduler (on do_sched_setscheduler with pid policy sched_priority=param->sched_priority) You can now use it in all perf tools, such as: perf record -e probe:do_sched_setscheduler -aR sleep 1 # cat /sys/kernel/debug/tracing/kprobe_events p:probe/do_sched_setscheduler _text+1113792 pid=%di:s32 policy=%si:s32 sched_priority=+u0(%dx):s32 # Fixes: 1e032f7cfa14 ("perf-probe: Add user memory access attribute support") Signed-off-by: Sumanth Korikkar Reviewed-by: Thomas Richter Acked-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Heiko Carstens Cc: Ilya Leoshkevich Cc: Jiri Olsa Cc: Steven Rostedt (VMware) Cc: bpf@vger.kernel.org LPU-Reference: 20200609081019.60234-2-sumanthk@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

perf probe: Check address correctness by map instead of _etext

2020-06-22T07:33:12Z

commit 2ae5d0d7d8868df7c05c2013c0b9cddd4d40610e upstream. Since commit 03db8b583d1c ("perf tools: Fix maps__find_symbol_by_name()") introduced map address range check in maps__find_symbol_by_name(), we can not get "_etext" from kernel map because _etext is placed on the edge of the kernel .text section (= kernel map in perf.) To fix this issue, this checks the address correctness by map address range information (map->start and map->end) instead of using _etext address. This can cause an error if the target inlined function is embedded in both __init function and normal function. For exaample, request_resource() is a normal function but also embedded in __init reserve_setup(). In this case, the probe point in reserve_setup() must be skipped. However, without this fix, it failes to setup all probe points: # ./perf probe -v request_resource probe-definition(0): request_resource symbol:request_resource file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /usr/lib/debug/lib/modules/5.5.17-200.fc31.x86_64/vmlinux for symbols Open Debuginfo file: /usr/lib/debug/lib/modules/5.5.17-200.fc31.x86_64/vmlinux Try to find probe point from debuginfo. Matched function: request_resource [15e29ad] found inline addr: 0xffffffff82fbf892 Probe point found: reserve_setup+204 found inline addr: 0xffffffff810e9790 Probe point found: request_resource+0 Found 2 probe_trace_events. Opening /sys/kernel/debug/tracing//kprobe_events write=1 Opening /sys/kernel/debug/tracing//README write=0 Writing event: p:probe/request_resource _text+33290386 Failed to write event: Invalid argument Error: Failed to add events. Reason: Invalid argument (Code: -22) # With this fix, # ./perf probe request_resource reserve_setup is out of .text, skip it. Added new events: (null):(null) (on request_resource) probe:request_resource (on request_resource) You can now use it in all perf tools, such as: perf record -e probe:request_resource -aR sleep 1 # Fixes: 03db8b583d1c ("perf tools: Fix maps__find_symbol_by_name()") Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/158763967332.30755.4922496724365529088.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf probe: Fix to check blacklist address correctly

2020-06-22T07:33:12Z

commit 80526491c2ca6abc028c0f0dbb0707a1f35fb18a upstream. Fix to check kprobe blacklist address correctly with relocated address by adjusting debuginfo address. Since the address in the debuginfo is same as objdump, it is different from relocated kernel address with KASLR. Thus, 'perf probe' always misses to catch the blacklisted addresses. Without this patch, 'perf probe' can not detect the blacklist addresses on a KASLR enabled kernel. # perf probe kprobe_dispatcher Failed to write event: Invalid argument Error: Failed to add events. # With this patch, it correctly shows the error message. # perf probe kprobe_dispatcher kprobe_dispatcher is blacklisted function, skip it. Probe point 'kprobe_dispatcher' not found. Error: Failed to add events. # Fixes: 9aaf5a5f479b ("perf probe: Check kprobes blacklist when adding new events") Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/158763966411.30755.5882376357738273695.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf probe: Accept the instance number of kretprobe event

2020-06-17T14:42:45Z

[ Upstream commit c6aab66a728b6518772c74bd9dff66e1a1c652fd ] Since the commit 6a13a0d7b4d1 ("ftrace/kprobe: Show the maxactive number on kprobe_events") introduced to show the instance number of kretprobe events, the length of the 1st format of the kprobe event will not 1, but it can be longer. This caused a parser error in perf-probe. Skip the length check the 1st format of the kprobe event to accept this instance number. Without this fix: # perf probe -a vfs_read%return Added new event: probe:vfs_read__return (on vfs_read%return) You can now use it in all perf tools, such as: perf record -e probe:vfs_read__return -aR sleep 1 # perf probe -l Semantic error :Failed to parse event name: r16:probe/vfs_read__return Error: Failed to show event list. And with this fixes: # perf probe -a vfs_read%return ... # perf probe -l probe:vfs_read__return (on vfs_read%return) Fixes: 6a13a0d7b4d1 ("ftrace/kprobe: Show the maxactive number on kprobe_events") Reported-by: Yuxuan Shui Signed-off-by: Masami Hiramatsu Tested-by: Yuxuan Shui Cc: Jiri Olsa Cc: Namhyung Kim Cc: stable@vger.kernel.org Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207587 Link: http://lore.kernel.org/lkml/158877535215.26469.1113127926699134067.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

perf maps: Rename map_groups.h to maps.h

2019-11-26T14:07:46Z

One more step in the merge of 'struct maps' with 'struct map_groups'. Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-9ibtn3vua76f934t7woyf26w@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf maps: Merge 'struct maps' with 'struct map_groups'

2019-11-26T14:07:46Z

And pick the shortest name: 'struct maps'. The split existed because we used to have two groups of maps, one for functions and one for variables, but that only complicated things, sometimes we needed to figure out what was at some address and then had to first try it on the functions group and if that failed, fall back to the variables one. That split is long gone, so for quite a while we had only one struct maps per struct map_groups, simplify things by combining those structs. First patch is the minimum needed to merge both, follow up patches will rename 'thread->mg' to 'thread->maps', etc. Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-hom6639ro7020o708trhxh59@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Trace a magic number if variable is not found

2019-11-18T22:09:23Z

Trace a magic number as immediate value if the target variable is not found at some probe points which is based on one probe event. This feature is good for the case if you trace a source code line with some local variables, which is compiled into several instructions and some of the variables are optimized out on some instructions. Even if so, with this feature, perf probe trace a magic number instead of such disappeared variables and fold those probes on one event. E.g. without this patch: # perf probe -D "pud_page_vaddr pud" Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. p:probe/pud_page_vaddr _text+23480787 pud=%ax:x64 p:probe/pud_page_vaddr _text+23808453 pud=%bp:x64 p:probe/pud_page_vaddr _text+23558082 pud=%ax:x64 p:probe/pud_page_vaddr _text+328373 pud=%r8:x64 p:probe/pud_page_vaddr _text+348448 pud=%bx:x64 p:probe/pud_page_vaddr _text+23816818 pud=%bx:x64 With this patch: # perf probe -D "pud_page_vaddr pud" | head spurious_kernel_fault is blacklisted function, skip it. vmalloc_fault is blacklisted function, skip it. p:probe/pud_page_vaddr _text+23480787 pud=%ax:x64 p:probe/pud_page_vaddr _text+149051 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+23808453 pud=%bp:x64 p:probe/pud_page_vaddr _text+315926 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+23807209 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+23557365 pud=%ax:x64 p:probe/pud_page_vaddr _text+314097 pud=%di:x64 p:probe/pud_page_vaddr _text+314015 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+313893 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+324083 pud=\deade12d:x64 Signed-off-by: Masami Hiramatsu Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Steven Rostedt (VMware) Cc: Tom Zanussi Link: http://lore.kernel.org/lkml/157406476931.24476.6261475888681844285.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Support multiprobe event

2019-11-18T22:03:38Z

Support multiprobe event if the event is based on function and lines and kernel supports it. In this case, perf probe creates the first probe with an event, and tries to append following probes on that event, since those probes must be on the same source code line. Before this patch; # perf probe -a vfs_read:18 Added new events: probe:vfs_read_L18 (on vfs_read:18) probe:vfs_read_L18_1 (on vfs_read:18) You can now use it in all perf tools, such as: perf record -e probe:vfs_read_L18_1 -aR sleep 1 # After this patch (on multiprobe supported kernel) # perf probe -a vfs_read:18 Added new events: probe:vfs_read_L18 (on vfs_read:18) probe:vfs_read_L18 (on vfs_read:18) You can now use it in all perf tools, such as: perf record -e probe:vfs_read_L18 -aR sleep 1 # Committer testing: On a kernel that doesn't support multiprobe events, after this patch: # uname -a Linux quaco 5.3.8-200.fc30.x86_64 #1 SMP Tue Oct 29 14:46:22 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux # grep append /sys/kernel/debug/tracing/README be modified by appending '.descending' or '.ascending' to a can be modified by appending any of the following modifiers # # perf probe -a vfs_read:18 Added new events: probe:vfs_read_L18 (on vfs_read:18) probe:vfs_read_L18_1 (on vfs_read:18) You can now use it in all perf tools, such as: perf record -e probe:vfs_read_L18_1 -aR sleep 1 # perf probe -l probe:vfs_read_L18 (on vfs_read:18@fs/read_write.c) probe:vfs_read_L18_1 (on vfs_read:18@fs/read_write.c) # Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Steven Rostedt (VMware) Cc: Tom Zanussi Link: http://lore.kernel.org/lkml/157406475010.24476.586290752591512351.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Generate event name with line number

2019-11-18T22:02:00Z

Generate event name from function name with line number as _L. Note that this is only for the new event which is defined by the line number of function (except for line 0). If there is another event on same line, you have to use "-f" option. In that case, the new event has "_1" suffix. e.g. # perf probe -a kernel_read:2 Added new event: probe:kernel_read_L2 (on kernel_read:2) You can now use it in all perf tools, such as: perf record -e probe:kernel_read_L2 -aR sleep 1 But if we omit the line number or 0th line, it will have no suffix. # perf probe -a kernel_read:0 Added new event: probe:kernel_read (on kernel_read) You can now use it in all perf tools, such as: perf record -e probe:kernel_read -aR sleep 1 probe:kernel_read (on kernel_read@linux-5.0.0/fs/read_write.c) probe:kernel_read_L2 (on kernel_read:2@linux-5.0.0/fs/read_write.c) Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Steven Rostedt (VMware) Cc: Tom Zanussi Link: http://lore.kernel.org/lkml/157406474026.24476.2828897745502059569.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo

perf maps: Add for_each_entry()/_safe() iterators

2019-11-06T18:49:25Z

To reduce boilerplate, provide a more compact form using an idiom present in other trees of data structures. Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-59gmq4kg1r68ou1wknyjl78x@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo