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alloc_tag: prevent enabling memory profiling if it was shut down

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Memory profiling can be shut down due to reasons like a failure during
initialization.  When this happens, the user should not be able to
re-enable it.  Current sysctrl interface does not handle this properly and
will allow re-enabling memory profiling.  Fix this by checking for this
condition during sysctrl write operation.

Link: https://lkml.kernel.org/r/20250915212756.3998938-3-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Usama Arif <usamaarif642@gmail.com>
Cc: David Wang <00107082@163.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Suren Baghdasaryan 2025-09-15 14:27:55 -07:00 • committed by Andrew Morton
parent 123bcf2842
commit 9e8a0bbb12
1 changed files with 15 additions and 1 deletions
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16
lib/alloc_tag.c
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@ -766,6 +766,20 @@ struct page_ext_operations page_alloc_tagging_ops = {
EXPORT_SYMBOL(page_alloc_tagging_ops);
#ifdef CONFIG_SYSCTL
/*
* Not using proc_do_static_key() directly to prevent enabling profiling
* after it was shut down.
*/
static int proc_mem_profiling_handler(const struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
if (!mem_profiling_support && write)
return -EINVAL;
return proc_do_static_key(table, write, buffer, lenp, ppos);
}
static struct ctl_table memory_allocation_profiling_sysctls[] = {
{
.procname = "mem_profiling",
@ -775,7 +789,7 @@ static struct ctl_table memory_allocation_profiling_sysctls[] = {
#else
.mode = 0644,
#endif
.proc_handler = proc_do_static_key,
.proc_handler = proc_mem_profiling_handler,
},
};