From nobody Sat Nov 22 16:53:15 2025 X-Original-To: freebsd-current@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4dDJ7X0wSkz6HRYP for ; Sat, 22 Nov 2025 16:53:28 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4dDJ7W3sRXz3SdC; Sat, 22 Nov 2025 16:53:27 +0000 (UTC) (envelope-from kostikbel@gmail.com) Authentication-Results: mx1.freebsd.org; none Received: from tom.home (kib@localhost [127.0.0.1] (may be forged)) by kib.kiev.ua (8.18.1/8.18.1) with ESMTP id 5AMGrF1e012994; Sat, 22 Nov 2025 18:53:18 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 5AMGrF1e012994 Received: (from kostik@localhost) by tom.home (8.18.1/8.18.1/Submit) id 5AMGrF3w012993; Sat, 22 Nov 2025 18:53:15 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 22 Nov 2025 18:53:15 +0200 From: Konstantin Belousov To: Michal Meloun Cc: FreeBSD Current Subject: Re: mmap( MAP_ANON) is broken on current. (was Still seeing Failed assertion: "p[i] == 0" on armv7 buildworld) Message-ID: References: <07201c46-6fb4-4514-aa88-490830edb010@freebsd.org> <603e75f8-7064-4fca-8520-282331c20ec0@freebsd.org> List-Id: Discussions about the use of FreeBSD-current List-Archive: https://lists.freebsd.org/archives/freebsd-current List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-current@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spamd-Bar: ---- X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US] X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Queue-Id: 4dDJ7W3sRXz3SdC On Sat, Nov 22, 2025 at 05:37:19PM +0100, Michal Meloun wrote: > > > On 22.11.2025 16:40, Konstantin Belousov wrote: > > On Sat, Nov 22, 2025 at 03:31:24PM +0100, Michal Meloun wrote: > > > This patch KASSERTs almost immediately when the system enters multi-user > > > mode while processing mmap() syscall: > > > > > > panic: vm_object_coalesce: obj 0xc73ddb28 next_pindex 0x13 next_size 0x5 > > > obj_size 0x176 > > > > Yes, the assert was mis-placed. Please try this variant. > > > > commit 2b1a1bcd2926bd89b8422c665b0aa411e29c883b > > Author: Konstantin Belousov > > Date: Sat Nov 22 16:02:50 2025 +0200 > > > > vm_object_coalesce(): fix logic to detect coalesce possibility, simplify > > > > diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c > > index 5b4517d2bf0c..9bb4e54edd96 100644 > > --- a/sys/vm/vm_object.c > > +++ b/sys/vm/vm_object.c > > @@ -2189,13 +2189,19 @@ vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, > > next_size >>= PAGE_SHIFT; > > next_pindex = OFF_TO_IDX(prev_offset) + prev_size; > > - if (prev_object->ref_count > 1 && > > - prev_object->size != next_pindex && > > + if (prev_object->ref_count > 1 || > > + prev_object->size != next_pindex || > > (prev_object->flags & OBJ_ONEMAPPING) == 0) { > > VM_OBJECT_WUNLOCK(prev_object); > > return (FALSE); > > } > > + KASSERT(next_pindex + next_size > prev_object->size, > > + ("vm_object_coalesce: " > > + "obj %p next_pindex %#jx next_size %#jx obj_size %#jx", > > + prev_object, (uintmax_t)next_pindex, (uintmax_t)next_size, > > + (uintmax_t)prev_object->size)); > > + > > /* > > * Account for the charge. > > */ > > @@ -2222,26 +2228,13 @@ vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, > > * Remove any pages that may still be in the object from a previous > > * deallocation. > > */ > > - if (next_pindex < prev_object->size) { > > - vm_object_page_remove(prev_object, next_pindex, next_pindex + > > - next_size, 0); > > -#if 0 > > - if (prev_object->cred != NULL) { > > - KASSERT(prev_object->charge >= > > - ptoa(prev_object->size - next_pindex), > > - ("object %p overcharged 1 %jx %jx", prev_object, > > - (uintmax_t)next_pindex, (uintmax_t)next_size)); > > - prev_object->charge -= ptoa(prev_object->size - > > - next_pindex); > > - } > > -#endif > > - } > > + vm_object_page_remove(prev_object, next_pindex, next_pindex + > > + next_size, 0); > > /* > > * Extend the object if necessary. > > */ > > - if (next_pindex + next_size > prev_object->size) > > - prev_object->size = next_pindex + next_size; > > + prev_object->size = next_pindex + next_size; > > VM_OBJECT_WUNLOCK(prev_object); > > return (TRUE); > > Unfortunately, that didn't help. I will try the vm_map.c patch again for > confirmation. Would you please gather the same ddebugging info, with this patch applied?