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Petersen (Oracle)" , Sasha Levin Subject: [PATCH 6.18 0454/1005] scsi: snic: Fix SCSI host leak on workqueue allocation failure Date: Wed, 4 Nov 2026 16:03:07 -0500 Message-ID: <20261104211056.758487796@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chen Changcheng [ Upstream commit 12e67eb89eb2b9516685c744d3f7de0a2d1bd701 ] In snic_add_host(), if scsi_add_host() succeeds but alloc_ordered_workqueue() fails, the function returns -ENOMEM with shost->work_q left as NULL. The caller's error path then calls snic_del_host(), which returns early when !shost->work_q without calling scsi_remove_host(). The Scsi_Host remains registered in sysfs as a zombie device even after the probe has failed. This causes: - The leaked host remains visible in /sys/class/scsi_host/ after probe failure, with state "running". - Subsequent SCSI host numbering is permanently shifted (the leaked host ID from ida_alloc() is never reclaimed). - Memory leak: the Scsi_Host allocation can never be freed because device_add() took a reference that can only be released by device_del() inside scsi_remove_host(). Fix by adding scsi_remove_host() in the workqueue allocation failure path inside snic_add_host(), undoing the successful scsi_add_host() before returning the error. This is cleaner than modifying snic_del_host() because snic_del_host() is called from a shared error label that also serves paths where snic_add_host() was never invoked. Reproducer (requires no real SNIC hardware): - Build CONFIG_SCSI_SNIC=y (built-in) - Add snic.test_mode=1 snic.inject_wq_fail=1 to kernel cmdline - Boot with a PCI device matching the snic driver (e.g. QEMU edu device, PCI ID 0x1234:0x11e8, temporarily added to the driver's PCI ID table) Before the fix: # /sys/class/scsi_host/ contains a zombie host0: $ cat /sys/class/scsi_host/host0/proc_name snic_scsi $ cat /sys/class/scsi_host/host0/state running # ata_piix gets host1, host2 (host0 stuck): scsi host1: ata_piix scsi host2: ata_piix After the fix: # host0 is properly freed and reused by ata_piix: scsi host0: ata_piix scsi host1: ata_piix # No zombie host in /sys/class/scsi_host/ Signed-off-by: Chen Changcheng Acked-by: Narsimhulu Musini Link: https://patch.msgid.link/20260727073438.209673-1-chenchangcheng@kylinos.cn Signed-off-by: Martin K. Petersen (Oracle) Signed-off-by: Sasha Levin --- drivers/scsi/snic/snic_main.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/scsi/snic/snic_main.c b/drivers/scsi/snic/snic_main.c index 1c24517e4e650..912f9f15dddc3 100644 --- a/drivers/scsi/snic/snic_main.c +++ b/drivers/scsi/snic/snic_main.c @@ -305,6 +305,7 @@ snic_add_host(struct Scsi_Host *shost, struct pci_dev *pdev) if (!shost->work_q) { SNIC_HOST_ERR(shost, "Failed to Create ScsiHost wq.\n"); + scsi_remove_host(shost); ret = -ENOMEM; } -- 2.53.0