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Howlett" , Nico Pache , Ryan Roberts , Barry Song , Lance Yang , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260501075708.327217-1-ye.liu@linux.dev> Content-Language: en-US From: Dev Jain In-Reply-To: <20260501075708.327217-1-ye.liu@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: frzb7dmn3jrmpcijpgom8rtrjif8f5sb X-Rspam-User: X-Rspamd-Queue-Id: 3D88E40007 X-Rspamd-Server: rspam07 X-HE-Tag: 1777632067-63462 X-HE-Meta: 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 Xs6dtZnP 9whLwgiC1QvZbES3JRAkrI6+sIM4ljbqlQZjILHuTZjcszz8dbABGKQ/zrzb8v7Q134iQhnFpAr0ZmHP6eox2PiYq6SqKwx1zxdyW696uwoO1TTNnlRdwYAVhz8ARIagTrbSGTSJrgRHIQjKjGu9SvuSipcu4Tfh86mHfcgqX2ojuENBnDbbbxIX52ZZTAE1qlRFzabnaH2AQQWmO7oucUnWoNr0h7pmhdFU3NePFlzwUJWoOOdLk+63NZXu1CeACF1Iq3SRo7YB2HEAw3/RQaccfi9GOakYRWPzP Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 01/05/26 1:27 pm, Ye Liu wrote: > From: Ye Liu > > __khugepaged_enter() sets MMF_VM_HUGEPAGE before allocating the > corresponding mm_slot. If mm_slot_alloc() fails, the function > returns with the flag set but without inserting the mm into the > khugepaged tracking structures. > > This leaves the mm in an inconsistent state: it is marked as > registered (MMF_VM_HUGEPAGE set), but will never be scanned by > khugepaged. Future attempts to register the mm are skipped since > khugepaged_enter_vma() checks the flag and returns early. > > Fix this by clearing MMF_VM_HUGEPAGE when mm_slot_alloc() fails, > restoring the ability to retry registration later. > > Signed-off-by: Ye Liu > --- > mm/khugepaged.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 7d48d4fbd5f3..60ab7c1b61dd 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -559,8 +559,10 @@ void __khugepaged_enter(struct mm_struct *mm) > return; > > slot = mm_slot_alloc(mm_slot_cache); > - if (!slot) > + if (!slot) { > + mm_flags_clear(MMF_VM_HUGEPAGE, mm); > return; > + } You could just move the test_and_set() after this no? So if slot allocation fails then MMF_VM_HUGEPAGE is never set. Fixes tag is probably required but not sure about Ccing stable. > > spin_lock(&khugepaged_mm_lock); > mm_slot_insert(mm_slots_hash, mm, slot);