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GET /api/patches/2231663/?format=api
{ "id": 2231663, "url": "http://patchwork.ozlabs.org/api/patches/2231663/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/8fda3212a1ad48879c174e92f67472d9b9f1c3b7.1777606826.git.ritesh.list@gmail.com/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/projects/2/?format=api", "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/", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/", "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/", "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}" }, "msgid": "<8fda3212a1ad48879c174e92f67472d9b9f1c3b7.1777606826.git.ritesh.list@gmail.com>", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/8fda3212a1ad48879c174e92f67472d9b9f1c3b7.1777606826.git.ritesh.list@gmail.com/", "date": "2026-05-01T04:11:44", "name": "[v3,5/9] pseries/papr-hvpipe: Fix the usage of copy_to_user()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "4c72be5772b08c33f82b9bb035c85b8214dc3c6b", "submitter": { "id": 79126, "url": "http://patchwork.ozlabs.org/api/people/79126/?format=api", "name": "Ritesh Harjani (IBM)", "email": "ritesh.list@gmail.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/8fda3212a1ad48879c174e92f67472d9b9f1c3b7.1777606826.git.ritesh.list@gmail.com/mbox/", "series": [ { "id": 502420, "url": "http://patchwork.ozlabs.org/api/series/502420/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=502420", "date": "2026-05-01T04:11:39", "name": "pseries/papr-hvpipe: Fix deadlock, races and misc cleanups", "version": 3, "mbox": "http://patchwork.ozlabs.org/series/502420/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2231663/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2231663/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "\n <linuxppc-dev+bounces-20356-incoming=patchwork.ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=SJpvlPnY;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=112.213.38.117; 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If there was\nan error writing bytes into the user buffer, i.e. if copy_to_user\nreturns a non-zero value, then we should simply return -EFAULT from the\n->read() call.\n\nOtherwise, in the non-patched version, we may end up mixing\n\"bytes_not_copied + bytes_copied (HVPIPE_HDR_LEN)\" as the return value\nto the user in ->read() call\n\nAlso let's make sure we clear the hvpipe_status flag, if we have\nconsumed the hvpipe msg by making the rtas call. ret = -EFAULT means\ncopy_to_user has failed but that still means that the msg was read from\nthe hvpipe, hence for both cases, success & -EFAULT, we should clear the\nHVPIPE_MSG_AVAILABLE flag in hvpipe_status.\n\nCc: stable@vger.kernel.org\nFixes: cebdb522fd3edd1 (\"powerpc/pseries: Receive payload with ibm,receive-hvpipe-msg RTAS\")\nSigned-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>\n---\n arch/powerpc/platforms/pseries/papr-hvpipe.c | 23 ++++++++++++--------\n 1 file changed, 14 insertions(+), 9 deletions(-)", "diff": "diff --git a/arch/powerpc/platforms/pseries/papr-hvpipe.c b/arch/powerpc/platforms/pseries/papr-hvpipe.c\nindex 800649f309a5..c007560d2d8c 100644\n--- a/arch/powerpc/platforms/pseries/papr-hvpipe.c\n+++ b/arch/powerpc/platforms/pseries/papr-hvpipe.c\n@@ -206,10 +206,11 @@ static int hvpipe_rtas_recv_msg(char __user *buf, int size)\n \t\t\t\t\tbytes_written, size);\n \t\t\t\tbytes_written = size;\n \t\t\t}\n-\t\t\tret = copy_to_user(buf,\n+\t\t\tif (copy_to_user(buf,\n \t\t\t\t\trtas_work_area_raw_buf(work_area),\n-\t\t\t\t\tbytes_written);\n-\t\t\tif (!ret)\n+\t\t\t\t\tbytes_written))\n+\t\t\t\tret = -EFAULT;\n+\t\t\telse\n \t\t\t\tret = bytes_written;\n \t\t}\n \t} else {\n@@ -328,7 +329,7 @@ static ssize_t papr_hvpipe_handle_read(struct file *file,\n \n \tstruct hvpipe_source_info *src_info = file->private_data;\n \tstruct papr_hvpipe_hdr hdr = {};\n-\tlong ret;\n+\tssize_t ret = 0;\n \n \t/*\n \t * Return -ENXIO during migration\n@@ -376,7 +377,7 @@ static ssize_t papr_hvpipe_handle_read(struct file *file,\n \n \tret = copy_to_user(buf, &hdr, HVPIPE_HDR_LEN);\n \tif (ret)\n-\t\treturn ret;\n+\t\treturn -EFAULT;\n \n \t/*\n \t * Message event has payload, so get the payload with\n@@ -385,19 +386,23 @@ static ssize_t papr_hvpipe_handle_read(struct file *file,\n \tif (hdr.flags & HVPIPE_MSG_AVAILABLE) {\n \t\tret = hvpipe_rtas_recv_msg(buf + HVPIPE_HDR_LEN,\n \t\t\t\tsize - HVPIPE_HDR_LEN);\n-\t\tif (ret > 0) {\n+\t\t/*\n+\t\t * Always clear MSG_AVAILABLE once the RTAS call has drained\n+\t\t * the message, regardless of whether copy_to_user succeeded.\n+\t\t */\n+\t\tif (ret >= 0 || ret == -EFAULT)\n \t\t\tsrc_info->hvpipe_status &= ~HVPIPE_MSG_AVAILABLE;\n-\t\t\tret += HVPIPE_HDR_LEN;\n-\t\t}\n \t} else if (hdr.flags & HVPIPE_LOST_CONNECTION) {\n \t\t/*\n \t\t * Hypervisor is closing the pipe for the specific\n \t\t * source. So notify user space.\n \t\t */\n \t\tsrc_info->hvpipe_status &= ~HVPIPE_LOST_CONNECTION;\n-\t\tret = HVPIPE_HDR_LEN;\n \t}\n \n+\tif (ret >= 0)\n+\t\tret += HVPIPE_HDR_LEN;\n+\n \treturn ret;\n }\n \n", "prefixes": [ "v3", "5/9" ] }