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Mon, 13 Jul 2026 17:26:02 +0000 (GMT) Received: from IBM-D32RQW3.ibm.com (unknown [9.61.249.24]) by smtpav02.dal12v.mail.ibm.com (Postfix) with ESMTP; Mon, 13 Jul 2026 17:26:02 +0000 (GMT) From: Farhan Ali To: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org Cc: alifm@linux.ibm.com, mjrosato@linux.ibm.com, borntraeger@linux.ibm.com Subject: [PATCH v1 1/5] KVM: s390: pci: Fix refcount leak in memory accounting functions Date: Mon, 13 Jul 2026 10:25:56 -0700 Message-ID: <20260713172600.1284-2-alifm@linux.ibm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260713172600.1284-1-alifm@linux.ibm.com> References: <20260713172600.1284-1-alifm@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 0oXW_xZKOV05omybnikgWhZYYzwtgjXX X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzEzMDE3OCBTYWx0ZWRfXx/eAsNckJtow oFLzhxZRACNYnnMrCt+XmL0KFjf5MSEd/lfqzJNJB6PsDGpjIakiySJtYyqvT8A/xXDmEBtcbPr /wwMWUDaigqL9ieVyNKqzzloFsBk6A5Ra5p44N5jgb4RhKS8srv5SZFyJRIogrZpvYU++g//2Qs /Bri5GO8xzhn0hqd9oWka3htLD6r/R5bMT9dwHtWdGyZ4Q2Ko/k5ltJr/vKJEHGfOjM6GsJ+0fD kCvwPuMcrlN5hTtpPSzPUUgmYxV+zzXrtd+WHyO8oJsr+C6NYuyD5/1tA9wKnwuPVhQuKcVBNrL QcDMzoBY3HZ3VSFO0t4atODPtpRA+6R7OKyIBrs4w8MJ65vrymwe/KffZNlhWSAjuPQ48oyweEq hXPoJuaNCXx/NZnTvUw9/WuNzEwtU8HsyxdfqPFZJSRaKzBbe6mZTF5cRIqdEG8GdB3y3VbkeIJ bNoR65Yql98/sg6340g== X-Authority-Analysis: v=2.4 cv=XJoAjwhE c=1 sm=1 tr=0 ts=6a551fac cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=D-MSj2RqzxEEtpeRmKsA:9 X-Proofpoint-ORIG-GUID: 0oXW_xZKOV05omybnikgWhZYYzwtgjXX X-Proofpoint-Spam-Info: AW1haW4tMjYwNzEzMDE3OCBTYWx0ZWRfX97JHaF4DJ5A2 UFfRzIFXK4k3/vdFUFBuXPm9nTna6ZOtMSBUE5fLPqC4dhfhauOsnU7rJ7ybQR4OpS1koJhunzT tiaIzJiIm8L/WU2MzgPum0zziseQ2EI= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-13_04,2026-07-10_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 bulkscore=0 phishscore=0 lowpriorityscore=0 priorityscore=1501 impostorscore=0 clxscore=1011 spamscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607130178 The account_mem() and unaccount_mem() functions call get_uid() which increments the reference count of struct user_struct on every invocation. But we don't decrement the count by calling free_uid(). Fix this by calling the free_uid() appropriately. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Signed-off-by: Farhan Ali --- arch/s390/kvm/pci.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c index 720bb58cabe2..5bbbb1de4b5a 100644 --- a/arch/s390/kvm/pci.c +++ b/arch/s390/kvm/pci.c @@ -198,25 +198,32 @@ static inline void unaccount_mem(unsigned long nr_pages) atomic_long_sub(nr_pages, &user->locked_vm); if (current->mm) atomic64_sub(nr_pages, ¤t->mm->pinned_vm); + + free_uid(user); } static inline int account_mem(unsigned long nr_pages) { struct user_struct *user = get_uid(current_user()); unsigned long page_limit, cur_pages, new_pages; + int rc = 0; page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; cur_pages = atomic_long_read(&user->locked_vm); do { new_pages = cur_pages + nr_pages; - if (new_pages > page_limit) - return -ENOMEM; + if (new_pages > page_limit) { + rc = -ENOMEM; + goto out; + } } while (!atomic_long_try_cmpxchg(&user->locked_vm, &cur_pages, new_pages)); atomic64_add(nr_pages, ¤t->mm->pinned_vm); - return 0; +out: + free_uid(user); + return rc; } static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, -- 2.43.0