Subject: linux-next: manual merge of the sysctl tree with the bpf-next tree

From: Stephen Rothwell <[email-masked]>
Date: Wed, 11 May 2022 16:33:00 +1000

Hi all,

Today's linux-next merge of the sysctl tree got a conflict in:

  kernel/trace/ftrace.c

between commit:

  bed0d9a50dac ("ftrace: Add ftrace_lookup_symbols function")

from the bpf-next tree and commit:

  8e4e83b2278b ("ftrace: move sysctl_ftrace_enabled to ftrace.c")

from the sysctl tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

-- 
Cheers,
Stephen Rothwell

diff --cc kernel/trace/ftrace.c
index 07d87c7a525d,1f89039f0feb..000000000000
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@@ -7965,64 -7969,21 +7969,83 @@@ ftrace_enable_sysctl(struct ctl_table *
  	return ret;
  }
  
+ static struct ctl_table ftrace_sysctls[] = {
+ 	{
+ 		.procname       = "ftrace_enabled",
+ 		.data           = &ftrace_enabled,
+ 		.maxlen         = sizeof(int),
+ 		.mode           = 0644,
+ 		.proc_handler   = ftrace_enable_sysctl,
+ 	},
+ 	{}
+ };
+ 
+ static int __init ftrace_sysctl_init(void)
+ {
+ 	register_sysctl_init("kernel", ftrace_sysctls);
+ 	return 0;
+ }
+ late_initcall(ftrace_sysctl_init);
+ #endif
++
 +static int symbols_cmp(const void *a, const void *b)
 +{
 +	const char **str_a = (const char **) a;
 +	const char **str_b = (const char **) b;
 +
 +	return strcmp(*str_a, *str_b);
 +}
 +
 +struct kallsyms_data {
 +	unsigned long *addrs;
 +	const char **syms;
 +	size_t cnt;
 +	size_t found;
 +};
 +
 +static int kallsyms_callback(void *data, const char *name,
 +			     struct module *mod, unsigned long addr)
 +{
 +	struct kallsyms_data *args = data;
 +
 +	if (!bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp))
 +		return 0;
 +
 +	addr = ftrace_location(addr);
 +	if (!addr)
 +		return 0;
 +
 +	args->addrs[args->found++] = addr;
 +	return args->found == args->cnt ? 1 : 0;
 +}
 +
 +/**
 + * ftrace_lookup_symbols - Lookup addresses for array of symbols
 + *
 + * @sorted_syms: array of symbols pointers symbols to resolve,
 + * must be alphabetically sorted
 + * @cnt: number of symbols/addresses in @syms/@addrs arrays
 + * @addrs: array for storing resulting addresses
 + *
 + * This function looks up addresses for array of symbols provided in
 + * @syms array (must be alphabetically sorted) and stores them in
 + * @addrs array, which needs to be big enough to store at least @cnt
 + * addresses.
 + *
 + * This function returns 0 if all provided symbols are found,
 + * -ESRCH otherwise.
 + */
 +int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
 +{
 +	struct kallsyms_data args;
 +	int err;
 +
 +	args.addrs = addrs;
 +	args.syms = sorted_syms;
 +	args.cnt = cnt;
 +	args.found = 0;
 +	err = kallsyms_on_each_symbol(kallsyms_callback, &args);
 +	if (err < 0)
 +		return err;
 +	return args.found == args.cnt ? 0 : -ESRCH;
 +}