104 lines
3.7 KiB
Diff
104 lines
3.7 KiB
Diff
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From 60d65f1f07a7d81d3eb3b91fc13fca80f2fdbb12 Mon Sep 17 00:00:00 2001
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From: Tyler Hicks <tyhicks@canonical.com>
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Date: Mon, 11 Jun 2012 10:21:34 -0700
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Subject: eCryptfs: Fix lockdep warning in miscdev operations
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From: Tyler Hicks <tyhicks@canonical.com>
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commit 60d65f1f07a7d81d3eb3b91fc13fca80f2fdbb12 upstream.
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Don't grab the daemon mutex while holding the message context mutex.
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Addresses this lockdep warning:
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ecryptfsd/2141 is trying to acquire lock:
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(&ecryptfs_msg_ctx_arr[i].mux){+.+.+.}, at: [<ffffffffa029c213>] ecryptfs_miscdev_read+0x143/0x470 [ecryptfs]
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but task is already holding lock:
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(&(*daemon)->mux){+.+...}, at: [<ffffffffa029c2ec>] ecryptfs_miscdev_read+0x21c/0x470 [ecryptfs]
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which lock already depends on the new lock.
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the existing dependency chain (in reverse order) is:
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-> #1 (&(*daemon)->mux){+.+...}:
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[<ffffffff810a3b8d>] lock_acquire+0x9d/0x220
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[<ffffffff8151c6da>] __mutex_lock_common+0x5a/0x4b0
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[<ffffffff8151cc64>] mutex_lock_nested+0x44/0x50
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[<ffffffffa029c5d7>] ecryptfs_send_miscdev+0x97/0x120 [ecryptfs]
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[<ffffffffa029b744>] ecryptfs_send_message+0x134/0x1e0 [ecryptfs]
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[<ffffffffa029a24e>] ecryptfs_generate_key_packet_set+0x2fe/0xa80 [ecryptfs]
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[<ffffffffa02960f8>] ecryptfs_write_metadata+0x108/0x250 [ecryptfs]
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[<ffffffffa0290f80>] ecryptfs_create+0x130/0x250 [ecryptfs]
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[<ffffffff811963a4>] vfs_create+0xb4/0x120
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[<ffffffff81197865>] do_last+0x8c5/0xa10
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[<ffffffff811998f9>] path_openat+0xd9/0x460
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[<ffffffff81199da2>] do_filp_open+0x42/0xa0
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[<ffffffff81187998>] do_sys_open+0xf8/0x1d0
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[<ffffffff81187a91>] sys_open+0x21/0x30
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[<ffffffff81527d69>] system_call_fastpath+0x16/0x1b
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-> #0 (&ecryptfs_msg_ctx_arr[i].mux){+.+.+.}:
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[<ffffffff810a3418>] __lock_acquire+0x1bf8/0x1c50
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[<ffffffff810a3b8d>] lock_acquire+0x9d/0x220
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[<ffffffff8151c6da>] __mutex_lock_common+0x5a/0x4b0
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[<ffffffff8151cc64>] mutex_lock_nested+0x44/0x50
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[<ffffffffa029c213>] ecryptfs_miscdev_read+0x143/0x470 [ecryptfs]
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[<ffffffff811887d3>] vfs_read+0xb3/0x180
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[<ffffffff811888ed>] sys_read+0x4d/0x90
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[<ffffffff81527d69>] system_call_fastpath+0x16/0x1b
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Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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fs/ecryptfs/miscdev.c | 25 +++++++++++++------------
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1 file changed, 13 insertions(+), 12 deletions(-)
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--- a/fs/ecryptfs/miscdev.c
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+++ b/fs/ecryptfs/miscdev.c
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@@ -195,31 +195,32 @@ int ecryptfs_send_miscdev(char *data, si
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struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
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u16 msg_flags, struct ecryptfs_daemon *daemon)
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{
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- int rc = 0;
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+ struct ecryptfs_message *msg;
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- mutex_lock(&msg_ctx->mux);
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- msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size),
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- GFP_KERNEL);
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- if (!msg_ctx->msg) {
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- rc = -ENOMEM;
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+ msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
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+ if (!msg) {
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printk(KERN_ERR "%s: Out of memory whilst attempting "
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"to kmalloc(%zd, GFP_KERNEL)\n", __func__,
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- (sizeof(*msg_ctx->msg) + data_size));
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- goto out_unlock;
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+ (sizeof(*msg) + data_size));
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+ return -ENOMEM;
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}
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+
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+ mutex_lock(&msg_ctx->mux);
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+ msg_ctx->msg = msg;
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msg_ctx->msg->index = msg_ctx->index;
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msg_ctx->msg->data_len = data_size;
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msg_ctx->type = msg_type;
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memcpy(msg_ctx->msg->data, data, data_size);
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msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
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- mutex_lock(&daemon->mux);
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list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
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+ mutex_unlock(&msg_ctx->mux);
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+
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+ mutex_lock(&daemon->mux);
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daemon->num_queued_msg_ctx++;
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wake_up_interruptible(&daemon->wait);
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mutex_unlock(&daemon->mux);
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-out_unlock:
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- mutex_unlock(&msg_ctx->mux);
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- return rc;
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+
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+ return 0;
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}
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/*
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