From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBB49CA0EDC for ; Thu, 14 Aug 2025 08:37:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5158B900112; Thu, 14 Aug 2025 04:37:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 470BF900088; Thu, 14 Aug 2025 04:37:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3602F900112; Thu, 14 Aug 2025 04:37:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 25038900088 for ; Thu, 14 Aug 2025 04:37:40 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id E11651DD909 for ; Thu, 14 Aug 2025 08:37:39 +0000 (UTC) X-FDA: 83774709438.02.A6DB5F5 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf08.hostedemail.com (Postfix) with ESMTP id 2C351160008 for ; Thu, 14 Aug 2025 08:37:37 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=j6oXdcgV; spf=pass (imf08.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1755160658; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=cpcplE9GK+U01o+94FQbXtHCnB3QDoQF4QT+tsJzRxc=; b=FHihV+jOkjN3SSB33rzKn4SBFwLjX5xNfKhoOF8BLBBw2RLVxZI9cfXImAFtVJNrBZuKgF kWI7FosP44Px1Ro7mBuuroiTxtVe5LDVvNXqrAV1Iu1ndRhmJFStJvbB3af/pOniezE4fI EfKNhkIDui5PmZoPVqL/C6WKgSTGlJ4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1755160658; a=rsa-sha256; cv=none; b=DibeTb8ey/RFrdyGmB/tKUyEdy8+UELX3KL8ioYreKXsvC0VGpC31aVjeEWP83XnoJSM8+ iIR+tuXD2D/t9keRnQA+zRO7dir9UAYzkIVmvr2AvcvZ1HATq0nSBGNui6FeozzHAzK/3S ZodDYLfeVHR/RLnjqaRVqd4UkF7zs7A= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=j6oXdcgV; spf=pass (imf08.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id CDF3945BD2; Thu, 14 Aug 2025 08:37:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35236C4CEEF; Thu, 14 Aug 2025 08:37:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755160656; bh=ySpcFEqW6mx248pQaNRvOQVwo6ykQE7J6nfU5QTBWiE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=j6oXdcgVciv/6BykGif5185QIWWX9Vff7Gxpuxu1c1XK1or/K4wIhNhT+pes02G9K zNvEs9K7QoOxvFG6Fw6noFJ20aHFitgr//ZwU3ghWpn8hW+AZTT8MPYTZwBmVsq1BP LtAHwk+FdENWA+tnwN91riEqFzg7OMFUoCJOD8tWN/cLUZAp5E/TlJ4I9v8XQTwYoA +hgzErxjxvLrVN6Sg/aAGfeSYznXOQeiDmqdUmH9KK7FNbXA0BzTgKv7hIbx3uYcaC 1Q2vqEreet9nlLsh5+8IyBPu0V3x30wCUzSOutTeO/X0ojmjwMiGayPIX3+Z7mxNOI OH9otFL1/ZPiQ== Date: Thu, 14 Aug 2025 11:37:14 +0300 From: Mike Rapoport To: Lorenzo Stoakes Cc: Andrew Morton , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , "David S . Miller" , Andreas Larsson , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Alexander Viro , Christian Brauner , Jan Kara , Kees Cook , David Hildenbrand , Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Xu Xin , Chengming Zhou , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , David Rientjes , Shakeel Butt , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , Masami Hiramatsu , Oleg Nesterov , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Jason Gunthorpe , John Hubbard , Peter Xu , Jann Horn , Pedro Falcato , Matthew Wilcox , Mateusz Guzik , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH 06/10] mm: update coredump logic to correctly use bitmap mm flags Message-ID: References: <2a5075f7e3c5b367d988178c79a3063d12ee53a9.1755012943.git.lorenzo.stoakes@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2a5075f7e3c5b367d988178c79a3063d12ee53a9.1755012943.git.lorenzo.stoakes@oracle.com> X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 2C351160008 X-Stat-Signature: esys9twqtzf75cdfft3nmerdpmrjbnix X-HE-Tag: 1755160657-693806 X-HE-Meta: U2FsdGVkX1+Czyc1hqAmKWCW3au11P/thhsGilnlkNJmy+3b/PHFIjT5d8ZL+vxq2DbLrVK4UCh6s+qWIkLJXifdlRVdRm5EmyokRnkOL7j+ftLEhH314IuXq8KVxPCdto85CoRk344aKrnjBNVuOZjZzrDiHTg7Jrcy6g/1Yvj1GJUCFni1t4lWH+z79ABdxSZt8aZKr1L50PgHRlWpDPkiccjxbWlk2phKlIvgkuxWBUVkmNrAoTAUfSRocrcrzpZ5WgN8lqF25q/P3/ItQJUBh6VXP2Tdy60fSU3VtrYJkA+6nsV/3THQAOjYeh7QeMHgTO78WvuIVzs5cuoyh6GYkn4mInyJLIFZQVFnw/MTB8kIg2IOLF20rGmN++a//E3qpJJK++j8fGLYwLQ25jJJgyGfdHTzt7shjoHVVE0d0pV74JzXBZfGtutTQh1QwqjnecZ+uBcXm+KIYBrP5TyrABQmY6TdrLxTugAfZLeQw6ldKbs9IIYQqofQpo/QD3YWmDUBqiZxYgK6TlfPDCF/+IB/pVdnZ40B5OfcWMzCGmcwgZXm/9nvSm8XiMNiIfScIG9eOvz/TDdOgSCrw9KJGKykxdeEXrMYBUU4ReCEpuZqmRDyTLMnuS1SIM0dRzBmQroik8aGHhaHc6YGCK7tadLTbaRURC9dDuAi9Uiw/PO/P/t+Ih4Qkmu0nvzPo7nb0r8vWDqPuR8rqS6Gvhxaz6STL7IBCyvGwG1FYxLnanj/Xas7GCbJ2v9zYHhVE2KNb3ZMUaLkxoFVvxnBkADUNrQZp5Qb3H0WqdGXWJMpS6AupoD8fp1BXcG8Z9QAk6+pSShsL5vb7TYgDbBIOvoSnjsA5gHTuzhiJTCBZAIjArNo0ghpCZN+e9e8TFriGcJE79egHBo4wMaCp60Nh/t4IaUa78q1ujvRnkCQKENXGK5Nb+GY+g2ffxRC/BK4rHfSOr2UeZkaPUrra4L Lto6Jc5V Z3ZjS0vuExhMTsKR6yhddPipKOLQ/SpI9lLGImAh1Ie4CLDSKqnpLMWmKupZHf5Nol82jMvMKD/LCgf4G284w3pV1pFkV5gVAhdn4CwzWihgHoLmuJxj8PjYqWZ6jCr3DlWoba9x893B2ZEJJJ8BZ33ZpIrM7tMHiOXULlfWKDK5gEE4kQk0BKpStW6ny5B4reGLLGR2naRP1q09ia3tTReXd/Fc9VCErhwgIRc2urRP3D0vwA0CKH84RgsFm7osknZcdvmDu0LxxQPXrhvOG2hXTAls6/LIz/wM6YYiuH/Y4aZfrDk6ttyE3iqhbn+S6hlYfL+f0bdFWkmY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 12, 2025 at 04:44:15PM +0100, Lorenzo Stoakes wrote: > The coredump logic is slightly different from other users in that it both > stores mm flags and additionally sets and gets using masks. > > Since the MMF_DUMPABLE_* flags must remain as they are for uABI reasons, > and of course these are within the first 32-bits of the flags, it is > reasonable to provide access to these in the same fashion so this logic can > all still keep working as it has been. > > Therefore, introduce coredump-specific helpers __mm_flags_get_dumpable() > and __mm_flags_set_mask_dumpable() for this purpose, and update all core > dump users of mm flags to use these. > > Signed-off-by: Lorenzo Stoakes Reviewed-by: Mike Rapoport (Microsoft) > --- > fs/coredump.c | 4 +++- > fs/exec.c | 2 +- > fs/pidfs.c | 7 +++++-- > fs/proc/base.c | 8 +++++--- > include/linux/sched/coredump.h | 21 ++++++++++++++++++++- > 5 files changed, 34 insertions(+), 8 deletions(-) > > diff --git a/fs/coredump.c b/fs/coredump.c > index fedbead956ed..e5d9d6276990 100644 > --- a/fs/coredump.c > +++ b/fs/coredump.c > @@ -1103,8 +1103,10 @@ void vfs_coredump(const kernel_siginfo_t *siginfo) > * We must use the same mm->flags while dumping core to avoid > * inconsistency of bit flags, since this flag is not protected > * by any locks. > + * > + * Note that we only care about MMF_DUMP* flags. > */ > - .mm_flags = mm->flags, > + .mm_flags = __mm_flags_get_dumpable(mm), > .vma_meta = NULL, > .cpu = raw_smp_processor_id(), > }; > diff --git a/fs/exec.c b/fs/exec.c > index 2a1e5e4042a1..dbac0e84cc3e 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -1999,7 +1999,7 @@ void set_dumpable(struct mm_struct *mm, int value) > if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) > return; > > - set_mask_bits(&mm->flags, MMF_DUMPABLE_MASK, value); > + __mm_flags_set_mask_dumpable(mm, value); > } > > SYSCALL_DEFINE3(execve, > diff --git a/fs/pidfs.c b/fs/pidfs.c > index edc35522d75c..5148b7646b7f 100644 > --- a/fs/pidfs.c > +++ b/fs/pidfs.c > @@ -357,8 +357,11 @@ static long pidfd_info(struct file *file, unsigned int cmd, unsigned long arg) > > if ((kinfo.mask & PIDFD_INFO_COREDUMP) && !(kinfo.coredump_mask)) { > task_lock(task); > - if (task->mm) > - kinfo.coredump_mask = pidfs_coredump_mask(task->mm->flags); > + if (task->mm) { > + unsigned long flags = __mm_flags_get_dumpable(task->mm); > + > + kinfo.coredump_mask = pidfs_coredump_mask(flags); > + } > task_unlock(task); > } > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 62d35631ba8c..f0c093c58aaf 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -2962,8 +2962,10 @@ static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf, > ret = 0; > mm = get_task_mm(task); > if (mm) { > + unsigned long flags = __mm_flags_get_dumpable(mm); > + > len = snprintf(buffer, sizeof(buffer), "%08lx\n", > - ((mm->flags & MMF_DUMP_FILTER_MASK) >> > + ((flags & MMF_DUMP_FILTER_MASK) >> > MMF_DUMP_FILTER_SHIFT)); > mmput(mm); > ret = simple_read_from_buffer(buf, count, ppos, buffer, len); > @@ -3002,9 +3004,9 @@ static ssize_t proc_coredump_filter_write(struct file *file, > > for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) { > if (val & mask) > - set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags); > + mm_flags_set(i + MMF_DUMP_FILTER_SHIFT, mm); > else > - clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags); > + mm_flags_clear(i + MMF_DUMP_FILTER_SHIFT, mm); > } > > mmput(mm); > diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h > index 6eb65ceed213..19ecfcceb27a 100644 > --- a/include/linux/sched/coredump.h > +++ b/include/linux/sched/coredump.h > @@ -2,12 +2,29 @@ > #ifndef _LINUX_SCHED_COREDUMP_H > #define _LINUX_SCHED_COREDUMP_H > > +#include > #include > > #define SUID_DUMP_DISABLE 0 /* No setuid dumping */ > #define SUID_DUMP_USER 1 /* Dump as user of process */ > #define SUID_DUMP_ROOT 2 /* Dump as root */ > > +static inline unsigned long __mm_flags_get_dumpable(struct mm_struct *mm) > +{ > + /* > + * By convention, dumpable bits are contained in first 32 bits of the > + * bitmap, so we can simply access this first unsigned long directly. > + */ > + return __mm_flags_get_word(mm); > +} > + > +static inline void __mm_flags_set_mask_dumpable(struct mm_struct *mm, int value) > +{ > + unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags); > + > + set_mask_bits(bitmap, MMF_DUMPABLE_MASK, value); > +} > + > extern void set_dumpable(struct mm_struct *mm, int value); > /* > * This returns the actual value of the suid_dumpable flag. For things > @@ -22,7 +39,9 @@ static inline int __get_dumpable(unsigned long mm_flags) > > static inline int get_dumpable(struct mm_struct *mm) > { > - return __get_dumpable(mm->flags); > + unsigned long flags = __mm_flags_get_dumpable(mm); > + > + return __get_dumpable(flags); > } > > #endif /* _LINUX_SCHED_COREDUMP_H */ > -- > 2.50.1 > -- Sincerely yours, Mike.