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Howlett" , Baoquan He , Pratyush Yadav , Pasha Tatashin , Jaroslav Kysela , Takashi Iwai , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Simona Vetter , Suren Baghdasaryan , Vlastimil Babka , Dave Young , linux-mm@kvack.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, kexec@lists.infradead.org, driver-core@lists.linux.dev Subject: [PATCH v2 2/3] kernfs: Unmap mmaps of removed files via file->f_mapping Date: Sat, 25 Jul 2026 21:05:48 +0000 Message-ID: <20260725210549.3716546-3-kwilczynski@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260725210549.3716546-1-kwilczynski@kernel.org> References: <20260725210549.3716546-1-kwilczynski@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 5667B2000B X-Stat-Signature: g9i9k7oijpk8x1ecqx6mwines3irtcz9 X-HE-Tag: 1785013563-820523 X-HE-Meta: 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 V1uNrwDF NDaT5gPZFh86lQnJqp/hPip07JtWHCAiYUJBfzwZyRIkrH8gdVvPxBFYV4X6oo1NWJM0VZ+rs+wraOjC3KuKBQOwkWcBOipTICOF6+po2f4z061tEp7ePr5rY/J8rBMoMpMZq46KCtOjm7TKy9tKl4mQLjBfP2HVsLfaFcObAMxNIQ3vQJrc4pprsTSXBxkLcMMZ3CBl4qDxi7I0G59yLqi50SFCHWrALkNyTsG7Ysn02TrDheuG9P+dC0KdmiyOLSgfU4VBZ6n0lSObliSaQch0fyv+0tbdctlbqo9Lc9oFEk2dGgj3fD+VInlXvLDziqCKI1SPdMbt2WSay9sIJGvfDXw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Currently, kernfs_drain_open_files() unmaps the mapping of the sysfs inode, file_inode(of->file)->i_mapping, when a node with mmapped open files is removed. Since commit 636b21b50152 ("PCI: Revoke mappings like devmem"), PCI resource and legacy sysfs files swap their f_mapping to iomem_get_mapping() at open time, so their VMAs are attached to the shared iomem address space, which the drain never unmaps. As a result, userspace mappings of PCI BARs survive device removal and BAR resize, keeping stale PTEs into physical address space that the kernel may have reassigned since. Thus, use unmap_mapping_file() for every open file, so that only the VMAs of the node being removed are zapped, while unrelated mappings are left intact. The same helper also covers files without a swapped f_mapping, and the driver-claim revocation through revoke_iomem() is unaffected, as those VMAs remain on the shared address space. This restores the behaviour these files had before the f_mapping swap was introduced. A read through a stale mapping after removal now raises SIGBUS instead of returning stale data. Fixes: 636b21b50152 ("PCI: Revoke mappings like devmem") Signed-off-by: Krzysztof Wilczyński --- fs/kernfs/file.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 8e0e90c93372..eb04439e9c3e 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -815,10 +815,8 @@ void kernfs_drain_open_files(struct kernfs_node *kn) } list_for_each_entry(of, &on->files, list) { - struct inode *inode = file_inode(of->file); - if (of->mmapped) { - unmap_mapping_range(inode->i_mapping, 0, 0, 1); + unmap_mapping_file(of->file); of->mmapped = false; on->nr_mmapped--; } -- 2.55.0