Hello, This patchset implements memory (address), stack[N], deference, bitfield and retval (it needs uretprobe tho) fetch methods for uprobes. It's based on the previous work [1] done by Hyeoncheol Lee.
Now kprobes and uprobes have their own fetch_type_tables and, in turn, memory and stack access methods. Other fetch methods are shared. For the dereference method, I added a new argument to fetch functions. It's because for uprobes it needs to know whether the given address is a file offset or a virtual address in an user process. For instance, in case of fetching from a memory directly (like @offset) it should convert the address (offset) to a virtual address of the process, but if it's a dereferencing, the given address already has the virtual address. To determine this in a fetch function, I passed a pointer to trace_uprobe for direct fetch, and passed NULL for dereference. The patch 1-2 are bug fixes and can be applied independently. Please look at patch 10 that uses per-cpu buffer for accessing user memory as suggested by Steven. While I tried hard not to mess things up there might be a chance I did something horrible. It'd be great if you guys take a look and give comments. * v6 changes: - add more Ack's from Masami - fix ref count of uprobe_cpu_buffer (thanks to Jovi) * v5 changes: - use user_stack_pointer() instead of GET_USP() - fix a bug in 'stack' fetch method of uprobes * v4 changes: - add Ack's from Masami - rearrange patches to make it easy for simple fixes to be applied - update documentation - use per-cpu buffer for storing args (thanks to Steve!) [1] https://lkml.org/lkml/2012/11/14/84 A simple example: # cat foo.c int glob = -1; char str[] = "hello uprobe."; struct foo { unsigned int unused: 2; unsigned int foo: 20; unsigned int bar: 10; } foo = { .foo = 5, }; int main(int argc, char *argv[]) { long local = 0x1234; return 127; } # gcc -o foo -g foo.c # objdump -d foo | grep -A9 -F '<main>' 00000000004004b0 <main>: 4004b0: 55 push %rbp 4004b1: 48 89 e5 mov %rsp,%rbp 4004b4: 89 7d ec mov %edi,-0x14(%rbp) 4004b7: 48 89 75 e0 mov %rsi,-0x20(%rbp) 4004bb: 48 c7 45 f8 34 12 00 movq $0x1234,-0x8(%rbp) 4004c2: 00 4004c3: b8 7f 00 00 00 mov $0x7f,%eax 4004c8: 5d pop %rbp 4004c9: c3 retq # nm foo | grep -e glob$ -e str -e foo 00000000006008bc D foo 00000000006008a8 D glob 00000000006008ac D str # perf probe -x /home/namhyung/tmp/foo -a 'foo=main+0x13 glob=@0x8a8:s32 \ > str=@0x8ac:string bit=@0x8bc:b10@2/32 argc=%di local=-0x8(%bp)' Added new event: probe_foo:foo (on 0x4c3 with glob=@0x8a8:s32 str=@0x8ac:string bit=@0x8bc:b10@2/32 argc=%di local=-0x8(%bp)) You can now use it in all perf tools, such as: perf record -e probe_foo:foo -aR sleep 1 # perf record -e probe_foo:foo ./foo [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.001 MB perf.data (~33 samples) ] # perf script | grep -v ^# foo 2008 [002 2199.867154: probe_foo:foo (4004c3) glob=-1 str="hello uprobe." bit=5 argc=1 local=1234 This patchset is based on the current for-next branch of the Steven Rostedt's linux-trace tree. I also put this on my 'uprobe/fetch-v6' branch in my tree: git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git Any comments are welcome, thanks. Namhyung Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Cc: Srikar Dronamraju <sri...@linux.vnet.ibm.com> Cc: Oleg Nesterov <o...@redhat.com> Cc: zhangwei(Jovi) <jovi.zhang...@huawei.com> Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net> Cc: Hemant Kumar <hks...@linux.vnet.ibm.com> Hyeoncheol Lee (2): tracing/kprobes: Move fetch functions to trace_kprobe.c tracing/kprobes: Add fetch{,_size} member into deref fetch method Namhyung Kim (11): tracing/uprobes: Fix documentation of uprobe registration syntax tracing/probes: Fix basic print type functions tracing/kprobes: Staticize stack and memory fetch functions tracing/kprobes: Factor out struct trace_probe tracing/uprobes: Convert to struct trace_probe tracing/kprobes: Move common functions to trace_probe.h tracing/kprobes: Integrate duplicate set_print_fmt() tracing/uprobes: Fetch args before reserving a ring buffer tracing/kprobes: Add priv argument to fetch functions tracing/uprobes: Add more fetch functions tracing/uprobes: Add support for full argument access methods Documentation/trace/uprobetracer.txt | 35 +- kernel/trace/trace_kprobe.c | 642 +++++++++++++++++++---------------- kernel/trace/trace_probe.c | 453 +++++++++--------------- kernel/trace/trace_probe.h | 202 ++++++++++- kernel/trace/trace_uprobe.c | 458 +++++++++++++++++-------- 5 files changed, 1063 insertions(+), 727 deletions(-) -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
