On Thu, 15 Mar 2018 11:05:01 -0700 Nick Kirsch <nick@xxxxxxxxxx> wrote: > Hi! > > I’m having some issues with symbol resolution; namely, perf probe > seems to think it’s happily attaching to the symbol > (nfs_readpages:362) I’m looking for and yet it shows up as a > different symbol (nfs_symlink_filter+36). I don't have a 3.10 kernel installed. Below you attach a probe to nfs_readpages:46, which is the 46th line after the function entry point. Can you do an objdump of the nfs.ko to see where nfs_symlink_filter is? As it may just be the symbol that corresponds to the location perf found reading the dwarf information. -- Steve > > I’d love some help! > > # uname -a > > Linux a-b06-u47 3.10.0-693.2.2.el7.x86_64 #1 SMP Sat Sep 9 03:55:24 > EDT 2017 x86_64 x86_64 x86_64 GNU/Linux > > # perf probe -v > -m /usr/lib/debug/lib/modules/3.10.0-693.2.2.el7.x86_64/kernel/fs/nfs/nfs.ko.debug > -a 'nfs_readpages:46 pgm->pg_bytes_written' probe-definition(0): > nfs_readpages:46 pgm->pg_bytes_written symbol:nfs_readpages > file:(null) line:46 offset:0 return:0 lazy:(null) parsing arg: > pgm->pg_bytes_written into pgm, pg_bytes_written(1) 1 arguments No > kprobe blacklist support, ignored Open Debuginfo > file: /usr/lib/debug/usr/lib/modules/3.10.0-693.2.2.el7.x86_64/kernel/fs/nfs/nfs.ko.debug > Try to find probe point from debuginfo. Matched function: > nfs_readpages [143625] Probe point found: nfs_readpages+362 > Searching 'pgm' variable in context. > Converting variable pgm into trace event. > converting pg_bytes_written in pgm > pg_bytes_written type is long unsigned int. > Found 1 probe_trace_events. > Opening /sys/kernel/debug/tracing//kprobe_events write=1 > Writing event: > p:probe/nfs_readpages /usr/lib/debug/usr/lib/modules/3.10.0-693.2.2.el7.x86_64/kernel/fs/nfs/nfs.ko.debug:nfs_symlink_filler+36 > pg_bytes_written=+16(%ax):u64 Added new event: probe:nfs_readpages > (on nfs_readpages:46 > in /usr/lib/debug/usr/lib/modules/3.10.0-693.2.2.el7.x86_64/kernel/fs/nfs/nfs.ko.debug > with pg_bytes_written=pgm->pg_bytes_written) > > [root@a-b06-u47 tracing]# cat kprobe_events > p:probe/nfs_readpages /usr/lib/debug/usr/lib/modules/3.10.0-693.2.2.el7.x86_64/kernel/fs/nfs/nfs.ko.debug:nfs_symlink_filler+36 > pg_bytes_written=+16(%ax):u64 > > > Thanks! > > Nick-- > To unsubscribe from this list: send the line "unsubscribe > linux-trace-users" in the body of a message to > majordomo@xxxxxxxxxxxxxxx More majordomo info at > http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-trace-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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