From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yunlong Song Subject: [PATCH v4] Revert "f2fs crypto: avoid unneeded memory allocation in ->readdir" Date: Wed, 28 Feb 2018 11:17:37 +0800 Message-ID: <1519787857-107910-1-git-send-email-yunlong.song@huawei.com> References: <1519463698-60555-1-git-send-email-yunlong.song@huawei.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1519463698-60555-1-git-send-email-yunlong.song@huawei.com> Sender: linux-kernel-owner@vger.kernel.org To: jaegeuk@kernel.org, chao@kernel.org, yuchao0@huawei.com, yunlong.song@icloud.com, yunlong.song@huawei.com Cc: miaoxie@huawei.com, bintian.wang@huawei.com, shengyong1@huawei.com, heyunlei@huawei.com, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org List-Id: linux-f2fs-devel.lists.sourceforge.net This reverts commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b. Conflicts: fs/f2fs/dir.c In some platforms (such as arm), high memory is used, then the decrypting filename will cause panic, the reason see commit 569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer for decrypting filename"): We got dentry pages from high_mem, and its address space directly goes into the decryption path via f2fs_fname_disk_to_usr. But, sg_init_one assumes the address is not from high_mem, so we can get this panic since it doesn't call kmap_high but kunmap_high is triggered at the end. kernel BUG at ../../../../../../kernel/mm/highmem.c:290! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM ... (kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4) (__kunmap_atomic+0xa0/0xa4) from [] (blkcipher_walk_done+0x128/0x1ec) (blkcipher_walk_done+0x128/0x1ec) from [] (crypto_cbc_decrypt+0xc0/0x170) (crypto_cbc_decrypt+0xc0/0x170) from [] (crypto_cts_decrypt+0xc0/0x114) (crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48) (async_decrypt+0x40/0x48) from [] (f2fs_fname_disk_to_usr+0x124/0x304) (f2fs_fname_disk_to_usr+0x124/0x304) from [] (f2fs_fill_dentries+0xac/0x188) (f2fs_fill_dentries+0xac/0x188) from [] (f2fs_readdir+0x1f0/0x300) (f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4) (vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc) (SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30) Howerver, later patch: commit e06f86e61d7a ("f2fs crypto: avoid unneeded memory allocation in ->readdir") reverts the codes, which causes panic again in arm, so fix it back to the old version. Signed-off-by: Yunlong Song Reviewed-by: Chao Yu --- fs/f2fs/dir.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index f00b5ed..de2e295 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, int save_len = fstr->len; int err; + de_name.name = f2fs_kmalloc(sbi, de_name.len, GFP_NOFS); + if (!de_name.name) + return -ENOMEM; + + memcpy(de_name.name, d->filename[bit_pos], de_name.len); + err = fscrypt_fname_disk_to_usr(d->inode, (u32)de->hash_code, 0, &de_name, fstr); + kfree(de_name.name); if (err) return err; -- 1.8.5.2