Re: [PATCH 5/9] lib/ref_tracker: improve allocation flags
From: Eric Dumazet <edumazet@google.com>
Date: 2022-02-17 15:13:32
Also in:
dri-devel, intel-gfx, lkml
On Thu, Feb 17, 2022 at 6:05 AM Andrzej Hajda [off-list ref] wrote:
Library can be called in non-sleeping context, so it should not use __GFP_NOFAIL. Instead it should calmly handle allocation fails, for this __GFP_NOWARN has been added as well.
Your commit changelog is misleading .
The GFP_NOFAIL issue has been fixed already in
commit c12837d1bb31032bead9060dec99ef310d5b9fb7 ("ref_tracker: use
__GFP_NOFAIL more carefully")
quoted hunk ↗ jump to hunk
Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> --- lib/ref_tracker.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c index 7b00bca300043..c8441ffbb058a 100644 --- a/lib/ref_tracker.c +++ b/lib/ref_tracker.c@@ -59,7 +59,7 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir, if (list_empty(&dir->list)) return; - sbuf = kmalloc(STACK_BUF_SIZE, GFP_NOWAIT); + sbuf = kmalloc(STACK_BUF_SIZE, GFP_NOWAIT | __GFP_NOWARN);
This belongs to patch 3 in your series.
quoted hunk ↗ jump to hunk
list_for_each_entry(tracker, &dir->list, head) ++total;@@ -154,11 +154,11 @@ int ref_tracker_alloc(struct ref_tracker_dir *dir, unsigned long entries[REF_TRACKER_STACK_ENTRIES]; struct ref_tracker *tracker; unsigned int nr_entries; - gfp_t gfp_mask = gfp;
Simply change this line to : gfp_t gfp_mask = gfp | __GFP_NOFAIL;
+ gfp_t gfp_mask;
unsigned long flags;Then leave all this code as is ? I find current code more readable.
quoted hunk ↗ jump to hunk
- if (gfp & __GFP_DIRECT_RECLAIM) - gfp_mask |= __GFP_NOFAIL; + gfp |= __GFP_NOWARN; + gfp_mask = (gfp & __GFP_DIRECT_RECLAIM) ? (gfp | __GFP_NOFAIL) : gfp; *trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask); if (unlikely(!tracker)) { pr_err_once("memory allocation failure, unreliable refcount tracker.\n");@@ -191,7 +191,8 @@ int ref_tracker_free(struct ref_tracker_dir *dir, } nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1); nr_entries = filter_irq_stacks(entries, nr_entries);
lib/ref_tracker.c got patches in net-next, your patch series is going to add conflicts. git log --oneline 5740d0689096..4d449bdc5b26 --no-merges -- lib/ref_tracker.c c2d1e3df4af59261777b39c2e47476acd4d1cbeb ref_tracker: remove filter_irq_stacks() call 8fd5522f44dcd7f05454ddc4f16d0f821b676cd9 ref_tracker: add a count of untracked references e3ececfe668facd87d920b608349a32607060e66 ref_tracker: implement use-after-free detection
- stack_handle = stack_depot_save(entries, nr_entries, GFP_ATOMIC); + stack_handle = stack_depot_save(entries, nr_entries, + GFP_NOWAIT | __GFP_NOWARN);
This is fine.
spin_lock_irqsave(&dir->lock, flags);
if (tracker->dead) {
--
2.25.1