{"id":2220913,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2220913/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/54c52b89a626627aa57191b67a3ee22710b46f7f.1775648406.git.ritesh.list@gmail.com/","project":{"id":2,"url":"http://patchwork.ozlabs.org/api/1.1/projects/2/?format=json","name":"Linux PPC development","link_name":"linuxppc-dev","list_id":"linuxppc-dev.lists.ozlabs.org","list_email":"linuxppc-dev@lists.ozlabs.org","web_url":"https://github.com/linuxppc/wiki/wiki","scm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git","webscm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/"},"msgid":"<54c52b89a626627aa57191b67a3ee22710b46f7f.1775648406.git.ritesh.list@gmail.com>","date":"2026-04-08T12:01:31","name":"[RFC,v2,01/10] pseries/papr-hvpipe: Fix race with interrupt handler","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"a49a2b25deb64bdcab5e8e2e06691b8762d503e2","submitter":{"id":79126,"url":"http://patchwork.ozlabs.org/api/1.1/people/79126/?format=json","name":"Ritesh Harjani (IBM)","email":"ritesh.list@gmail.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/54c52b89a626627aa57191b67a3ee22710b46f7f.1775648406.git.ritesh.list@gmail.com/mbox/","series":[{"id":499129,"url":"http://patchwork.ozlabs.org/api/1.1/series/499129/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=499129","date":"2026-04-08T12:01:30","name":"pseries/papr-hvpipe: Fix deadlock, races and misc cleanups","version":2,"mbox":"http://patchwork.ozlabs.org/series/499129/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2220913/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2220913/checks/","tags":{},"headers":{"Return-Path":"\n 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Bagalkote ,\n\tNicholas Piggin ,\n\tlinux-kernel@vger.kernel.org,\n\t\"Ritesh Harjani (IBM)\" ,\n\tstable@vger.kernel.org","Subject":"[RFC v2 01/10] pseries/papr-hvpipe: Fix race with interrupt handler","Date":"Wed, 8 Apr 2026 17:31:31 +0530","Message-ID":"\n <54c52b89a626627aa57191b67a3ee22710b46f7f.1775648406.git.ritesh.list@gmail.com>","X-Mailer":"git-send-email 2.50.1","In-Reply-To":"","References":"","X-Mailing-List":"linuxppc-dev@lists.ozlabs.org","List-Id":"","List-Help":"","List-Owner":"","List-Post":"","List-Archive":",\n ","List-Subscribe":",\n ,\n ","List-Unsubscribe":"","Precedence":"list","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Spam-Status":"No, score=-0.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID,\n\tDKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,SPF_HELO_NONE,SPF_PASS\n\tautolearn=disabled version=4.0.1 OzLabs 8","X-Spam-Checker-Version":"SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org"},"content":"While executing ->ioctl handler or ->release handler, if an interrupt\nfires on the same cpu, then we can enter into a deadlock.\n\nThis patch fixes both these handlers to take spin_lock_irq{save|restore}\nversions of the lock to prevent this deadlock.\n\nCc: stable@vger.kernel.org\nFixes: 814ef095f12c9 (\"powerpc/pseries: Add papr-hvpipe char driver for HVPIPE interfaces\")\nSigned-off-by: Ritesh Harjani (IBM) \n---\n arch/powerpc/platforms/pseries/papr-hvpipe.c | 20 +++++++++++---------\n 1 file changed, 11 insertions(+), 9 deletions(-)","diff":"diff --git a/arch/powerpc/platforms/pseries/papr-hvpipe.c b/arch/powerpc/platforms/pseries/papr-hvpipe.c\nindex 14ae480d060a..c41d45e1986d 100644\n--- a/arch/powerpc/platforms/pseries/papr-hvpipe.c\n+++ b/arch/powerpc/platforms/pseries/papr-hvpipe.c\n@@ -444,13 +444,14 @@ static int papr_hvpipe_handle_release(struct inode *inode,\n \t\t\t\tstruct file *file)\n {\n \tstruct hvpipe_source_info *src_info;\n+\tunsigned long flags;\n \n \t/*\n \t * Hold the lock, remove source from src_list, reset the\n \t * hvpipe status and release the lock to prevent any race\n \t * with message event IRQ.\n \t */\n-\tspin_lock(&hvpipe_src_list_lock);\n+\tspin_lock_irqsave(&hvpipe_src_list_lock, flags);\n \tsrc_info = file->private_data;\n \tlist_del(&src_info->list);\n \tfile->private_data = NULL;\n@@ -461,10 +462,10 @@ static int papr_hvpipe_handle_release(struct inode *inode,\n \t */\n \tif (src_info->hvpipe_status & HVPIPE_MSG_AVAILABLE) {\n \t\tsrc_info->hvpipe_status = 0;\n-\t\tspin_unlock(&hvpipe_src_list_lock);\n+\t\tspin_unlock_irqrestore(&hvpipe_src_list_lock, flags);\n \t\thvpipe_rtas_recv_msg(NULL, 0);\n \t} else\n-\t\tspin_unlock(&hvpipe_src_list_lock);\n+\t\tspin_unlock_irqrestore(&hvpipe_src_list_lock, flags);\n \n \tkfree(src_info);\n \treturn 0;\n@@ -480,20 +481,21 @@ static const struct file_operations papr_hvpipe_handle_ops = {\n static int papr_hvpipe_dev_create_handle(u32 srcID)\n {\n \tstruct hvpipe_source_info *src_info __free(kfree) = NULL;\n+\tunsigned long flags;\n \n-\tspin_lock(&hvpipe_src_list_lock);\n+\tspin_lock_irqsave(&hvpipe_src_list_lock, flags);\n \t/*\n \t * Do not allow more than one process communicates with\n \t * each source.\n \t */\n \tsrc_info = hvpipe_find_source(srcID);\n \tif (src_info) {\n-\t\tspin_unlock(&hvpipe_src_list_lock);\n+\t\tspin_unlock_irqrestore(&hvpipe_src_list_lock, flags);\n \t\tpr_err(\"pid(%d) is already using the source(%d)\\n\",\n \t\t\t\tsrc_info->tsk->pid, srcID);\n \t\treturn -EALREADY;\n \t}\n-\tspin_unlock(&hvpipe_src_list_lock);\n+\tspin_unlock_irqrestore(&hvpipe_src_list_lock, flags);\n \n \tsrc_info = kzalloc_obj(*src_info, GFP_KERNEL_ACCOUNT);\n \tif (!src_info)\n@@ -510,18 +512,18 @@ static int papr_hvpipe_dev_create_handle(u32 srcID)\n \t\treturn fdf.err;\n \n \tretain_and_null_ptr(src_info);\n-\tspin_lock(&hvpipe_src_list_lock);\n+\tspin_lock_irqsave(&hvpipe_src_list_lock, flags);\n \t/*\n \t * If two processes are executing ioctl() for the same\n \t * source ID concurrently, prevent the second process to\n \t * acquire FD.\n \t */\n \tif (hvpipe_find_source(srcID)) {\n-\t\tspin_unlock(&hvpipe_src_list_lock);\n+\t\tspin_unlock_irqrestore(&hvpipe_src_list_lock, flags);\n \t\treturn -EALREADY;\n \t}\n \tlist_add(&src_info->list, &hvpipe_src_list);\n-\tspin_unlock(&hvpipe_src_list_lock);\n+\tspin_unlock_irqrestore(&hvpipe_src_list_lock, flags);\n \treturn fd_publish(fdf);\n }\n \n","prefixes":["RFC","v2","01/10"]}