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From: Usama Arif In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 40152100004 X-Stat-Signature: yan38o7u3nfpkb4fk9c16gwffd3giuwi X-HE-Tag: 1780489212-652249 X-HE-Meta: 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 FKpFs0rj aJW0t/SZaNomda/6KXWOV0JQv0Pcq03jUGhr8T7l/L50CcvBc5R7a7XO2dGsuGBEoX4AP/ACnFRhqtZii/YxdQVtuqDsdp7cRAkworT329rxZmO9U/Ml+AGht8fI4ouqb1OczBo1Nh6ZgswNz5GWOVYZCNAMfHfn6dMCsYeBQHBSqROtNQOt1xS3TluPNLSvr0by5cmUp6YCd4yadgo41xTWMntjFX9wN6q9FWg3KJlkEGKLZ0nHy/gFnvj9eLxMg0CpOg+/AT9SEjbhuGeihkn8XJLcDhZCg8ctSuhnz2waJ9doFKeu7WJ6Ze7nujoPDWPnO Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 03/06/2026 13:08, Lorenzo Stoakes wrote: > On Tue, Jun 02, 2026 at 10:22:47AM -0700, Usama Arif wrote: >> mincore_swap() also fields migration/hwpoison entries (and shmem >> swapin-error entries), which can exist on !CONFIG_SWAP builds when >> CONFIG_MIGRATION or CONFIG_MEMORY_FAILURE is enabled. The >> !IS_ENABLED(CONFIG_SWAP) guard ran before the non-swap-entry early >> return, so mincore_pte_range() can spuriously WARN and report these >> pages nonresident on !CONFIG_SWAP kernels. >> >> Move the guard below the non-swap-entry check so only true swap >> entries trip the WARN, and migration/hwpoison entries take the >> existing "uptodate / non-shmem" path. >> >> Fixes: 1f2052755c15 ("mm/mincore: use a helper for checking the swap cache") >> Signed-off-by: Usama Arif > > Logic LGTM so: > > Reviewed-by: Lorenzo Stoakes > > Small note below but I think not a problem. > > Thanks, Lorenzo > >> --- >> This was discovered when working on PMD swap entry series >> (https://lore.kernel.org/all/20260602142537.198755-1-usama.arif@linux.dev/) >> --- >> mm/mincore.c | 10 +++++----- >> 1 file changed, 5 insertions(+), 5 deletions(-) >> >> diff --git a/mm/mincore.c b/mm/mincore.c >> index e5d13eea9234..296f2e3922b5 100644 >> --- a/mm/mincore.c >> +++ b/mm/mincore.c >> @@ -64,11 +64,6 @@ static unsigned char mincore_swap(swp_entry_t entry, bool shmem) >> struct folio *folio = NULL; >> unsigned char present = 0; >> >> - if (!IS_ENABLED(CONFIG_SWAP)) { >> - WARN_ON(1); >> - return 0; >> - } >> - >> /* >> * Shmem mapping may contain swapin error entries, which are >> * absent. Page table may contain migration or hwpoison >> @@ -77,6 +72,11 @@ static unsigned char mincore_swap(swp_entry_t entry, bool shmem) >> if (!softleaf_is_swap(entry)) >> return !shmem; >> > > I guess fine to do this after software_is_swap() because for !CONFIG_SWAP this > will always evaluate false? Yes, thats right. In softleaf_is_swap(), softleaf_type() returns SOFTLEAF_SWAP iff type_num < MAX_SWAPFILES. MAX_SWAPFILES is a compile-time constant independent of CONFIG_SWAP, so softleaf_is_swap() isn't structurally gated, but every producer of real swap entries lives under CONFIG_SWAP. With !CONFIG_SWAP none of those run, so softleaf_is_swap() is always false. > > Not a big deal therefore I think. > >> + if (!IS_ENABLED(CONFIG_SWAP)) { >> + WARN_ON(1); >> + return 0; >> + } >> + >> /* >> * Shmem mapping lookup is lockless, so we need to grab the swap >> * device. mincore page table walk locks the PTL, and the swap >> -- >> 2.52.0 >>