diff options
| author | Ran Xiaokai <ran.xiaokai@zte.com.cn> | 2026-01-15 03:15:36 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-01-31 14:22:37 -0800 |
| commit | 77bcee8d4015a1191e1e3f5c5c51589086493ab0 (patch) | |
| tree | 794e903d8b0ad2ae6359d076a2c71715b9ec0629 /lib | |
| parent | d468d8f86d80383e52ab6cf59e916b9f5578d46a (diff) | |
alloc_tag: fix rw permission issue when handling boot parameter
Boot parameters prefixed with "sysctl." are processed during the final
stage of system initialization via kernel_init()-> do_sysctl_args(). When
CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled, the sysctl.vm.mem_profiling
entry is not writable and will cause a warning.
Before run_init_process(), system initialization executes in kernel thread
context. Use current->mm to distinguish sysctl writes during
do_sysctl_args() from user-space triggered ones.
And when the proc_handler is from do_sysctl_args(), always return success
because the same value was already set by setup_early_mem_profiling() and
this eliminates a permission denied warning.
Link: https://lkml.kernel.org/r/20260115031536.164254-1-ranxiaokai627@163.com
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/alloc_tag.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index 846a5b5b44a4..00ae4673a271 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -776,8 +776,22 @@ EXPORT_SYMBOL(page_alloc_tagging_ops); 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; + if (write) { + /* + * Call from do_sysctl_args() which is a no-op since the same + * value was already set by setup_early_mem_profiling. + * Return success to avoid warnings from do_sysctl_args(). + */ + if (!current->mm) + return 0; + +#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG + /* User can't toggle profiling while debugging */ + return -EACCES; +#endif + if (!mem_profiling_support) + return -EINVAL; + } return proc_do_static_key(table, write, buffer, lenp, ppos); } @@ -787,11 +801,7 @@ static const struct ctl_table memory_allocation_profiling_sysctls[] = { { .procname = "mem_profiling", .data = &mem_alloc_profiling_key, -#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG - .mode = 0444, -#else .mode = 0644, -#endif .proc_handler = proc_mem_profiling_handler, }, }; |