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author | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2009-05-10 22:41:43 +0900 |
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committer | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2009-05-11 14:54:41 +0900 |
commit | 4f6b828837b4e3836f2c9ac2f0eab9773b6c1327 (patch) | |
tree | 9baa69b0ef44a0c604be831300fd5215c0355be0 /fs/nilfs2/ioctl.c | |
parent | 47eb6b9c8fa963c9f49967ad1d9d7ec947d15b68 (diff) | |
download | linux-3.10-4f6b828837b4e3836f2c9ac2f0eab9773b6c1327.tar.gz linux-3.10-4f6b828837b4e3836f2c9ac2f0eab9773b6c1327.tar.bz2 linux-3.10-4f6b828837b4e3836f2c9ac2f0eab9773b6c1327.zip |
nilfs2: fix lock order reversal in nilfs_clean_segments ioctl
This is a companion patch to ("nilfs2: fix possible circular locking
for get information ioctls").
This corrects lock order reversal between mm->mmap_sem and
nilfs->ns_segctor_sem in nilfs_clean_segments() which was detected by
lockdep check:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.30-rc3-nilfs-00003-g360bdc1 #7
-------------------------------------------------------
mmap/5294 is trying to acquire lock:
(&nilfs->ns_segctor_sem){++++.+}, at: [<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
but task is already holding lock:
(&mm->mmap_sem){++++++}, at: [<c043700a>] do_page_fault+0x1d8/0x30a
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&mm->mmap_sem){++++++}:
[<c01470a5>] __lock_acquire+0x1066/0x13b0
[<c01474a9>] lock_acquire+0xba/0xdd
[<c01836bc>] might_fault+0x68/0x88
[<c023c61d>] copy_from_user+0x2a/0x111
[<d0d120d0>] nilfs_ioctl_prepare_clean_segments+0x1d/0xf1 [nilfs2]
[<d0d0e2aa>] nilfs_clean_segments+0x6d/0x1b9 [nilfs2]
[<d0d11f68>] nilfs_ioctl+0x2ad/0x318 [nilfs2]
[<c01a3be7>] vfs_ioctl+0x22/0x69
[<c01a408e>] do_vfs_ioctl+0x460/0x499
[<c01a4107>] sys_ioctl+0x40/0x5a
[<c01031a4>] sysenter_do_call+0x12/0x38
[<ffffffff>] 0xffffffff
-> #0 (&nilfs->ns_segctor_sem){++++.+}:
[<c0146e0b>] __lock_acquire+0xdcc/0x13b0
[<c01474a9>] lock_acquire+0xba/0xdd
[<c0433f1d>] down_read+0x2a/0x3e
[<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
[<d0cfe0e5>] nilfs_page_mkwrite+0xe7/0x154 [nilfs2]
[<c0183b0b>] __do_fault+0x165/0x376
[<c01855cd>] handle_mm_fault+0x287/0x5d1
[<c043712d>] do_page_fault+0x2fb/0x30a
[<c0435462>] error_code+0x72/0x78
[<ffffffff>] 0xffffffff
where nilfs_clean_segments() holds:
nilfs->ns_segctor_sem -> copy_from_user()
--> page fault -> mm->mmap_sem
And, page fault path may hold:
page fault -> mm->mmap_sem
--> nilfs_page_mkwrite() -> nilfs->ns_segctor_sem
Even though nilfs_clean_segments() does not perform write access on
given user pages, it may cause deadlock because nilfs->ns_segctor_sem
is shared per device and mm->mmap_sem can be shared with other tasks.
To avoid this problem, this patch moves all calls of copy_from_user()
outside the nilfs->ns_segctor_sem lock in the ioctl.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Diffstat (limited to 'fs/nilfs2/ioctl.c')
-rw-r--r-- | fs/nilfs2/ioctl.c | 163 |
1 files changed, 93 insertions, 70 deletions
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c index e3c693d37d6..49489f68eab 100644 --- a/fs/nilfs2/ioctl.c +++ b/fs/nilfs2/ioctl.c @@ -25,6 +25,7 @@ #include <linux/smp_lock.h> /* lock_kernel(), unlock_kernel() */ #include <linux/capability.h> /* capable() */ #include <linux/uaccess.h> /* copy_from_user(), copy_to_user() */ +#include <linux/vmalloc.h> #include <linux/nilfs2_fs.h> #include "nilfs.h" #include "segment.h" @@ -297,10 +298,10 @@ static int nilfs_ioctl_move_inode_block(struct inode *inode, return 0; } -static ssize_t -nilfs_ioctl_do_move_blocks(struct the_nilfs *nilfs, __u64 *posp, int flags, - void *buf, size_t size, size_t nmembs) +static int nilfs_ioctl_move_blocks(struct the_nilfs *nilfs, + struct nilfs_argv *argv, void *buf) { + size_t nmembs = argv->v_nmembs; struct inode *inode; struct nilfs_vdesc *vdesc; struct buffer_head *bh, *n; @@ -361,19 +362,10 @@ nilfs_ioctl_do_move_blocks(struct the_nilfs *nilfs, __u64 *posp, int flags, return ret; } -static inline int nilfs_ioctl_move_blocks(struct the_nilfs *nilfs, - struct nilfs_argv *argv, - int dir) -{ - return nilfs_ioctl_wrap_copy(nilfs, argv, dir, - nilfs_ioctl_do_move_blocks); -} - -static ssize_t -nilfs_ioctl_do_delete_checkpoints(struct the_nilfs *nilfs, __u64 *posp, - int flags, void *buf, size_t size, - size_t nmembs) +static int nilfs_ioctl_delete_checkpoints(struct the_nilfs *nilfs, + struct nilfs_argv *argv, void *buf) { + size_t nmembs = argv->v_nmembs; struct inode *cpfile = nilfs->ns_cpfile; struct nilfs_period *periods = buf; int ret, i; @@ -387,36 +379,21 @@ nilfs_ioctl_do_delete_checkpoints(struct the_nilfs *nilfs, __u64 *posp, return nmembs; } -static inline int nilfs_ioctl_delete_checkpoints(struct the_nilfs *nilfs, - struct nilfs_argv *argv, - int dir) +static int nilfs_ioctl_free_vblocknrs(struct the_nilfs *nilfs, + struct nilfs_argv *argv, void *buf) { - return nilfs_ioctl_wrap_copy(nilfs, argv, dir, - nilfs_ioctl_do_delete_checkpoints); -} + size_t nmembs = argv->v_nmembs; + int ret; -static ssize_t -nilfs_ioctl_do_free_vblocknrs(struct the_nilfs *nilfs, __u64 *posp, int flags, - void *buf, size_t size, size_t nmembs) -{ - int ret = nilfs_dat_freev(nilfs_dat_inode(nilfs), buf, nmembs); + ret = nilfs_dat_freev(nilfs_dat_inode(nilfs), buf, nmembs); return (ret < 0) ? ret : nmembs; } -static inline int nilfs_ioctl_free_vblocknrs(struct the_nilfs *nilfs, - struct nilfs_argv *argv, - int dir) -{ - return nilfs_ioctl_wrap_copy(nilfs, argv, dir, - nilfs_ioctl_do_free_vblocknrs); -} - -static ssize_t -nilfs_ioctl_do_mark_blocks_dirty(struct the_nilfs *nilfs, __u64 *posp, - int flags, void *buf, size_t size, - size_t nmembs) +static int nilfs_ioctl_mark_blocks_dirty(struct the_nilfs *nilfs, + struct nilfs_argv *argv, void *buf) { + size_t nmembs = argv->v_nmembs; struct inode *dat = nilfs_dat_inode(nilfs); struct nilfs_bmap *bmap = NILFS_I(dat)->i_bmap; struct nilfs_bdesc *bdescs = buf; @@ -455,18 +432,10 @@ nilfs_ioctl_do_mark_blocks_dirty(struct the_nilfs *nilfs, __u64 *posp, return nmembs; } -static inline int nilfs_ioctl_mark_blocks_dirty(struct the_nilfs *nilfs, - struct nilfs_argv *argv, - int dir) -{ - return nilfs_ioctl_wrap_copy(nilfs, argv, dir, - nilfs_ioctl_do_mark_blocks_dirty); -} - -static ssize_t -nilfs_ioctl_do_free_segments(struct the_nilfs *nilfs, __u64 *posp, int flags, - void *buf, size_t size, size_t nmembs) +static int nilfs_ioctl_free_segments(struct the_nilfs *nilfs, + struct nilfs_argv *argv, void *buf) { + size_t nmembs = argv->v_nmembs; struct nilfs_sb_info *sbi = nilfs->ns_writer; int ret; @@ -481,31 +450,19 @@ nilfs_ioctl_do_free_segments(struct the_nilfs *nilfs, __u64 *posp, int flags, return (ret < 0) ? ret : nmembs; } -static inline int nilfs_ioctl_free_segments(struct the_nilfs *nilfs, - struct nilfs_argv *argv, - int dir) -{ - return nilfs_ioctl_wrap_copy(nilfs, argv, dir, - nilfs_ioctl_do_free_segments); -} - int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs, - void __user *argp) + struct nilfs_argv *argv, void **kbufs) { - struct nilfs_argv argv[5]; const char *msg; - int dir, ret; - - if (copy_from_user(argv, argp, sizeof(argv))) - return -EFAULT; + int ret; - dir = _IOC_WRITE; - ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], dir); + ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]); if (ret < 0) { msg = "cannot read source blocks"; goto failed; } - ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], dir); + + ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], kbufs[1]); if (ret < 0) { /* * can safely abort because checkpoints can be removed @@ -514,7 +471,7 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs, msg = "cannot delete checkpoints"; goto failed; } - ret = nilfs_ioctl_free_vblocknrs(nilfs, &argv[2], dir); + ret = nilfs_ioctl_free_vblocknrs(nilfs, &argv[2], kbufs[2]); if (ret < 0) { /* * can safely abort because DAT file is updated atomically @@ -523,7 +480,7 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs, msg = "cannot delete virtual blocks from DAT file"; goto failed; } - ret = nilfs_ioctl_mark_blocks_dirty(nilfs, &argv[3], dir); + ret = nilfs_ioctl_mark_blocks_dirty(nilfs, &argv[3], kbufs[3]); if (ret < 0) { /* * can safely abort because the operation is nondestructive. @@ -531,7 +488,7 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs, msg = "cannot mark copying blocks dirty"; goto failed; } - ret = nilfs_ioctl_free_segments(nilfs, &argv[4], dir); + ret = nilfs_ioctl_free_segments(nilfs, &argv[4], kbufs[4]); if (ret < 0) { /* * can safely abort because this operation is atomic. @@ -551,9 +508,75 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs, static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp, unsigned int cmd, void __user *argp) { + struct nilfs_argv argv[5]; + const static size_t argsz[5] = { + sizeof(struct nilfs_vdesc), + sizeof(struct nilfs_period), + sizeof(__u64), + sizeof(struct nilfs_bdesc), + sizeof(__u64), + }; + void __user *base; + void *kbufs[5]; + struct the_nilfs *nilfs; + size_t len, nsegs; + int n, ret; + if (!capable(CAP_SYS_ADMIN)) return -EPERM; - return nilfs_clean_segments(inode->i_sb, argp); + + if (copy_from_user(argv, argp, sizeof(argv))) + return -EFAULT; + + nsegs = argv[4].v_nmembs; + if (argv[4].v_size != argsz[4]) + return -EINVAL; + /* + * argv[4] points to segment numbers this ioctl cleans. We + * use kmalloc() for its buffer because memory used for the + * segment numbers is enough small. + */ + kbufs[4] = memdup_user((void __user *)(unsigned long)argv[4].v_base, + nsegs * sizeof(__u64)); + if (IS_ERR(kbufs[4])) + return PTR_ERR(kbufs[4]); + + nilfs = NILFS_SB(inode->i_sb)->s_nilfs; + + for (n = 0; n < 4; n++) { + ret = -EINVAL; + if (argv[n].v_size != argsz[n]) + goto out_free; + + if (argv[n].v_nmembs > nsegs * nilfs->ns_blocks_per_segment) + goto out_free; + + len = argv[n].v_size * argv[n].v_nmembs; + base = (void __user *)(unsigned long)argv[n].v_base; + if (len == 0) { + kbufs[n] = NULL; + continue; + } + + kbufs[n] = vmalloc(len); + if (!kbufs[n]) { + ret = -ENOMEM; + goto out_free; + } + if (copy_from_user(kbufs[n], base, len)) { + ret = -EFAULT; + vfree(kbufs[n]); + goto out_free; + } + } + + ret = nilfs_clean_segments(inode->i_sb, argv, kbufs); + + out_free: + while (--n > 0) + vfree(kbufs[n]); + kfree(kbufs[4]); + return ret; } static int nilfs_ioctl_sync(struct inode *inode, struct file *filp, |