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Revert "ftrace: Fix possible use-after-free issue in ftrace_location()"

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This reverts commit 2c12c9f7ef.
This commit is contained in:
Ksawlii 2024-11-24 00:23:31 +01:00
parent 0f1229f8a4
commit cf372342bd
1 changed files with 16 additions and 23 deletions
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39
kernel/trace/ftrace.c
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@ -1566,15 +1566,12 @@ static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
unsigned long ftrace_location_range(unsigned long start, unsigned long end)
{
struct dyn_ftrace *rec;
unsigned long ip = 0;
rcu_read_lock();
rec = lookup_rec(start, end);
if (rec)
ip = rec->ip;
rcu_read_unlock();
return rec->ip;
return ip;
return 0;
}
/**
@ -1587,22 +1584,25 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end)
*/
unsigned long ftrace_location(unsigned long ip)
{
unsigned long loc;
struct dyn_ftrace *rec;
unsigned long offset;
unsigned long size;
loc = ftrace_location_range(ip, ip);
if (!loc) {
rec = lookup_rec(ip, ip);
if (!rec) {
if (!kallsyms_lookup_size_offset(ip, &size, &offset))
goto out;
/* map sym+0 to __fentry__ */
if (!offset)
loc = ftrace_location_range(ip, ip + size - 1);
rec = lookup_rec(ip, ip + size - 1);
}
if (rec)
return rec->ip;
out:
return loc;
return 0;
}
/**
@ -6331,8 +6331,6 @@ static int ftrace_process_locs(struct module *mod,
/* We should have used all pages unless we skipped some */
if (pg_unuse) {
WARN_ON(!skipped);
/* Need to synchronize with ftrace_location_range() */
synchronize_rcu();
ftrace_free_pages(pg_unuse);
}
return ret;
@ -6515,9 +6513,6 @@ void ftrace_release_mod(struct module *mod)
out_unlock:
mutex_unlock(&ftrace_lock);
/* Need to synchronize with ftrace_location_range() */
if (tmp_page)
synchronize_rcu();
for (pg = tmp_page; pg; pg = tmp_page) {
/* Needs to be called outside of ftrace_lock */
@ -6840,7 +6835,6 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
unsigned long start = (unsigned long)(start_ptr);
unsigned long end = (unsigned long)(end_ptr);
struct ftrace_page **last_pg = &ftrace_pages_start;
struct ftrace_page *tmp_page = NULL;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
struct dyn_ftrace key;
@ -6884,8 +6878,12 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
ftrace_update_tot_cnt--;
if (!pg->index) {
*last_pg = pg->next;
pg->next = tmp_page;
tmp_page = pg;
if (pg->records) {
free_pages((unsigned long)pg->records, pg->order);
ftrace_number_of_pages -= 1 << pg->order;
}
ftrace_number_of_groups--;
kfree(pg);
pg = container_of(last_pg, struct ftrace_page, next);
if (!(*last_pg))
ftrace_pages = pg;
@ -6902,11 +6900,6 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
clear_func_from_hashes(func);
kfree(func);
}
/* Need to synchronize with ftrace_location_range() */
if (tmp_page) {
synchronize_rcu();
ftrace_free_pages(tmp_page);
}
}
void __init ftrace_free_init_mem(void)