On Fri, Aug 08, 2014 at 08:05:13PM +0900, Masami Hiramatsu wrote: > Ping?
For the series: Tested-by: Josh Poimboeuf <jpoim...@redhat.com> > > BTW, I'd like to add this testcase if ftracetest is accepted. > > Thank you, > > (2014/07/28 14:22), Masami Hiramatsu wrote: > > Hi, > > > > Here is the 4th version of the series of patches which introduces > > IPMODIFY flag for ftrace_ops to detect conflicts of ftrace users > > who can modify regs->ip in their handler. > > This version is basically an update of previous version, and > > I've splitted a patch which adding IPMODIFY to kprobes from ftrace > > IPMODIFY introducing patch. > > > > Currently, only kprobes can change the regs->ip in the handler, > > but recently kpatch is also want to change it. Moreover, since > > the ftrace itself exported to modules, it might be considerable > > senario. > > > > Here we talked on github. > > https://github.com/dynup/kpatch/issues/47 > > > > To protect modified regs-ip from each other, this series > > introduces FTRACE_OPS_FL_IPMODIFY flag and ftrace now ensures > > the flag can be set on each function entry location. If there > > is someone who already reserve regs->ip on target function > > entry, ftrace_set_filter_ip or register_ftrace_function will > > return -EBUSY. Users must handle that. > > The ftrace_ops with IPMODIFY flag requires at least one > > entry for filter hash, and its notrace_hash must be empty, > > because the IPMODIFY action is very address sensitve and > > user must consider the ip address. > > > > The 3rd patch adds a special reservation of IPMODIFY on the > > jprobed address, since it is the only user who will change > > the regs->ip. Other kprobes do not change it anymore. > > > > Here is the new testcase. > > ------- > > #!/bin/bash > > > > echo "IPMODIFY test" > > ADDR=0x`grep do_fork /proc/kallsyms | cut -f 1 -d" "` > > > > echo "Case1: kprobe->jprobe->ipmodify(fail)" > > modprobe kprobe_example > > modprobe jprobe_example > > insmod ./ipmodify.ko target=$ADDR && echo "Case1: [FAIL]" || echo "Case1: > > [OK]" > > rmmod kprobe_example jprobe_example > > > > echo "Case2: jprobe->kprobe->ipmodify(fail)" > > modprobe jprobe_example > > modprobe kprobe_example > > insmod ./ipmodify.ko target=$ADDR && echo "Case2: [FAIL]" || echo "Case2: > > [OK]" > > rmmod kprobe_example jprobe_example > > > > echo "Case3: jprobe->ipmodify(fail)" > > modprobe jprobe_example > > insmod ./ipmodify.ko target=$ADDR && echo "Case3: [FAIL]" || echo "Case3: > > [OK]" > > rmmod jprobe_example > > > > echo "Case4: ipmodify->jprobe(fail)" > > insmod ./ipmodify.ko target=$ADDR > > modprobe jprobe_example && echo "Case4: [FAIL]" || echo "Case4: [OK]" > > rmmod ipmodify > > > > echo "Case5: ipmodify->kprobe->jprobe(fail)" > > insmod ./ipmodify.ko target=$ADDR > > modprobe kprobe_example > > modprobe jprobe_example && echo "Case5: [FAIL]" || echo "Case5: [OK]" > > rmmod ipmodify kprobe_example > > > > echo "Case6: ipmodify with targeting all functions(fail)" > > insmod ./ipmodify.ko && echo "Case6: [FAIL]" || echo "Case6: [OK]" > > rmmod ipmodify > > > > echo "Case7: ipmodify with notrace filter (fail)" > > insmod ./ipmodify.ko target=$ADDR noexp="do_fork" && echo "Case7: [FAIL]" > > || echo "Case7: [OK]" > > rmmod ipmodify > > ------- > > > > And ipmodify.c > > ------- > > #include <linux/kernel.h> > > #include <linux/module.h> > > #include <linux/ftrace.h> > > > > > > static void ftrace_ipmodify_handler(unsigned long a0, unsigned long a1, > > struct ftrace_ops *op, struct pt_regs *regs) > > { > > return; > > } > > > > static struct ftrace_ops test_ops __read_mostly = { > > .func = ftrace_ipmodify_handler, > > .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, > > }; > > > > static unsigned long target; > > module_param(target, ulong, 0444); > > static char *noexp = ""; > > module_param(noexp, charp, 0444); > > > > static int __init ipmodify_init(void) > > { > > int ret; > > unsigned long ip = target; > > > > if (strlen(noexp) != 0) { > > ret = ftrace_set_notrace(&test_ops, noexp, 0, 0); > > pr_err("ipmodify_test: set notrace \"%s\", ret = %d\n", > > noexp, ret); > > } > > if (ret < 0) > > return ret; > > > > ret = ftrace_set_filter_ip(&test_ops, ip, 0, 0); > > pr_err("ipmodify_test: set filter ip 0x%lx, ret = %d\n", ip, ret); > > > > if (ret >= 0) { > > ret = register_ftrace_function(&test_ops); > > pr_err("ipmodify_test: register ftrace on 0x%lx, ret = > > %d\n", > > ip, ret); > > } > > > > return ret; > > } > > > > static void __exit ipmodify_exit(void) > > { > > int ret; > > unsigned long ip = target; > > > > ret = unregister_ftrace_function(&test_ops); > > pr_err("ipmodify_test: unregister ftrace on 0x%lx, ret = %d\n", ip, > > ret); > > if (ret >= 0) { > > ret = ftrace_set_filter_ip(&test_ops, ip, 1, 0); > > pr_err("ipmodify_test: clear filter ip 0x%lx, ret = %d\n", > > ip, ret); > > } > > } > > > > module_init(ipmodify_init) > > module_exit(ipmodify_exit) > > MODULE_LICENSE("GPL"); > > ------- > > > > Thank you, > > > > --- > > > > Masami Hiramatsu (4): > > kprobes/ftrace: Recover original IP if pre_handler doesn't change it > > ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict > > kprobes: Add IPMODIFY flag to kprobe_ftrace_ops > > kprobes: Set IPMODIFY flag only if the probe can change regs->ip > > > > > > Documentation/kprobes.txt | 12 +-- > > Documentation/trace/ftrace.txt | 5 + > > arch/x86/kernel/kprobes/ftrace.c | 9 ++ > > include/linux/ftrace.h | 16 ++++ > > kernel/kprobes.c | 123 +++++++++++++++++++++++++++++---- > > kernel/trace/ftrace.c | 143 > > +++++++++++++++++++++++++++++++++++++- > > 6 files changed, 279 insertions(+), 29 deletions(-) > > > > -- > > > > > > > -- > Masami HIRAMATSU > IT Management Research Dept. Linux Technology Center > Hitachi, Ltd., Yokohama Research Laboratory > E-mail: masami.hiramatsu...@hitachi.com > > -- Josh -- 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/