From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- fs/9p/cache.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 fs/9p/cache.c (limited to 'fs/9p/cache.c') diff --git a/fs/9p/cache.c b/fs/9p/cache.c new file mode 100644 index 000000000..12c0ae29f --- /dev/null +++ b/fs/9p/cache.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * V9FS cache definitions. + * + * Copyright (C) 2009 by Abhishek Kulkarni + */ + +#include +#include +#include +#include +#include +#include +#include + +#include "v9fs.h" +#include "cache.h" + +int v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses, + const char *dev_name) +{ + struct fscache_volume *vcookie; + char *name, *p; + + name = kasprintf(GFP_KERNEL, "9p,%s,%s", + dev_name, v9ses->cachetag ?: v9ses->aname); + if (!name) + return -ENOMEM; + + for (p = name; *p; p++) + if (*p == '/') + *p = ';'; + + vcookie = fscache_acquire_volume(name, NULL, NULL, 0); + p9_debug(P9_DEBUG_FSC, "session %p get volume %p (%s)\n", + v9ses, vcookie, name); + if (IS_ERR(vcookie)) { + if (vcookie != ERR_PTR(-EBUSY)) { + kfree(name); + return PTR_ERR(vcookie); + } + pr_err("Cache volume key already in use (%s)\n", name); + vcookie = NULL; + } + v9ses->fscache = vcookie; + kfree(name); + return 0; +} + +void v9fs_cache_inode_get_cookie(struct inode *inode) +{ + struct v9fs_inode *v9inode = V9FS_I(inode); + struct v9fs_session_info *v9ses; + __le32 version; + __le64 path; + + if (!S_ISREG(inode->i_mode)) + return; + if (WARN_ON(v9fs_inode_cookie(v9inode))) + return; + + version = cpu_to_le32(v9inode->qid.version); + path = cpu_to_le64(v9inode->qid.path); + v9ses = v9fs_inode2v9ses(inode); + v9inode->netfs.cache = + fscache_acquire_cookie(v9fs_session_cache(v9ses), + 0, + &path, sizeof(path), + &version, sizeof(version), + i_size_read(&v9inode->netfs.inode)); + if (v9inode->netfs.cache) + mapping_set_release_always(inode->i_mapping); + + p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n", + inode, v9fs_inode_cookie(v9inode)); +} -- cgit v1.3.1