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SubjectRe: [PATCH -next] kdb: Use newer api for tasklist scanning
On Mon, Aug 31, 2020 at 12:34:35PM -0700, Davidlohr Bueso wrote:
> This kills the custom kdb_do_each_thread/kdb_while_each_thread
> calls used in kdb to iterate through all tasks. It is obsolete
> and racy to use tsk->thread_group, although in this particular

No objections to the change but kdb doesn't use tsk->thread_group,
it uses do_each_thread/while_each_thread. Can we change this to
say that is osbsolete and racy to use while_each_thread() (that's
pretty much what the description of the patch that introduced
for_each_thread said)?

Additionally the debug_core uses do_each_thread/while_each_thread.
Presumably that would like to be changed as well?


Daniel.



> case there is no concurrency so it doesn't matter. Still, lets
> trivially replace it for the newer one, maintaining semantics,
> of course.
>
> Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> ---
> kernel/debug/kdb/kdb_bt.c | 4 ++--
> kernel/debug/kdb/kdb_main.c | 8 ++++----
> kernel/debug/kdb/kdb_private.h | 4 ----
> 3 files changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
> index 18e03aba2cfc..1f9f0e47aeda 100644
> --- a/kernel/debug/kdb/kdb_bt.c
> +++ b/kernel/debug/kdb/kdb_bt.c
> @@ -149,14 +149,14 @@ kdb_bt(int argc, const char **argv)
> return 0;
> }
> /* Now the inactive tasks */
> - kdb_do_each_thread(g, p) {
> + for_each_process_thread(g, p) {
> if (KDB_FLAG(CMD_INTERRUPT))
> return 0;
> if (task_curr(p))
> continue;
> if (kdb_bt1(p, mask, btaprompt))
> return 0;
> - } kdb_while_each_thread(g, p);
> + }
> } else if (strcmp(argv[0], "btp") == 0) {
> struct task_struct *p;
> unsigned long pid;
> diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
> index 5c7949061671..930ac1b25ec7 100644
> --- a/kernel/debug/kdb/kdb_main.c
> +++ b/kernel/debug/kdb/kdb_main.c
> @@ -2299,10 +2299,10 @@ void kdb_ps_suppressed(void)
> if (kdb_task_state(p, mask_I))
> ++idle;
> }
> - kdb_do_each_thread(g, p) {
> + for_each_process_thread(g, p) {
> if (kdb_task_state(p, mask_M))
> ++daemon;
> - } kdb_while_each_thread(g, p);
> + }
> if (idle || daemon) {
> if (idle)
> kdb_printf("%d idle process%s (state I)%s\n",
> @@ -2370,12 +2370,12 @@ static int kdb_ps(int argc, const char **argv)
> }
> kdb_printf("\n");
> /* Now the real tasks */
> - kdb_do_each_thread(g, p) {
> + for_each_process_thread(g, p) {
> if (KDB_FLAG(CMD_INTERRUPT))
> return 0;
> if (kdb_task_state(p, mask))
> kdb_ps1(p);
> - } kdb_while_each_thread(g, p);
> + }
>
> return 0;
> }
> diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
> index 2e296e4a234c..a4281fb99299 100644
> --- a/kernel/debug/kdb/kdb_private.h
> +++ b/kernel/debug/kdb/kdb_private.h
> @@ -230,10 +230,6 @@ extern struct task_struct *kdb_curr_task(int);
>
> #define kdb_task_has_cpu(p) (task_curr(p))
>
> -/* Simplify coexistence with NPTL */
> -#define kdb_do_each_thread(g, p) do_each_thread(g, p)
> -#define kdb_while_each_thread(g, p) while_each_thread(g, p)
> -
> #define GFP_KDB (in_interrupt() ? GFP_ATOMIC : GFP_KERNEL)
>
> extern void *debug_kmalloc(size_t size, gfp_t flags);
> --
> 2.26.2

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