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authorXiubo Li <xiubli@redhat.com>2019-02-13 16:29:36 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-15 08:09:14 +0100
commit5d07d245cb418064561c1a4e57313cf0a9132aa6 (patch)
treed60e96e6e29713e3e7fd20005dbc77487a8a373c
parent28c618abeee3380a4ead50fe9863b692dd851e07 (diff)
uio: fix possible circular locking dependency
commit b34e9a15b37b8ddbf06a4da142b0c39c74211eb4 upstream. The call trace: XXX/1910 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<ffffffff97008c87>] might_fault+0x57/0xb0 but task is already holding lock: (&idev->info_lock){+.+...}, at: [<ffffffffc0638a06>] uio_write+0x46/0x130 [uio] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&idev->info_lock){+.+...}: [<ffffffff96f31fc9>] lock_acquire+0x99/0x1e0 [<ffffffff975edad3>] mutex_lock_nested+0x93/0x410 [<ffffffffc063873d>] uio_mmap+0x2d/0x170 [uio] [<ffffffff97016b58>] mmap_region+0x428/0x650 [<ffffffff97017138>] do_mmap+0x3b8/0x4e0 [<ffffffff96ffaba3>] vm_mmap_pgoff+0xd3/0x120 [<ffffffff97015261>] SyS_mmap_pgoff+0x1f1/0x270 [<ffffffff96e387c2>] SyS_mmap+0x22/0x30 [<ffffffff975ff315>] system_call_fastpath+0x1c/0x21 -> #0 (&mm->mmap_sem){++++++}: [<ffffffff96f30e9c>] __lock_acquire+0xdac/0x15f0 [<ffffffff96f31fc9>] lock_acquire+0x99/0x1e0 [<ffffffff97008cb4>] might_fault+0x84/0xb0 [<ffffffffc0638a74>] uio_write+0xb4/0x130 [uio] [<ffffffff9706ffa3>] vfs_write+0xc3/0x1f0 [<ffffffff97070e2a>] SyS_write+0x8a/0x100 [<ffffffff975ff315>] system_call_fastpath+0x1c/0x21 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&idev->info_lock); lock(&mm->mmap_sem); lock(&idev->info_lock); lock(&mm->mmap_sem); *** DEADLOCK *** 1 lock held by XXX/1910: #0: (&idev->info_lock){+.+...}, at: [<ffffffffc0638a06>] uio_write+0x46/0x130 [uio] stack backtrace: CPU: 0 PID: 1910 Comm: XXX Kdump: loaded Not tainted #1 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 Call Trace: [<ffffffff975e9211>] dump_stack+0x19/0x1b [<ffffffff975e260a>] print_circular_bug+0x1f9/0x207 [<ffffffff96f2f6a7>] check_prevs_add+0x957/0x960 [<ffffffff96f30e9c>] __lock_acquire+0xdac/0x15f0 [<ffffffff96f2fb19>] ? mark_held_locks+0xb9/0x140 [<ffffffff96f31fc9>] lock_acquire+0x99/0x1e0 [<ffffffff97008c87>] ? might_fault+0x57/0xb0 [<ffffffff97008cb4>] might_fault+0x84/0xb0 [<ffffffff97008c87>] ? might_fault+0x57/0xb0 [<ffffffffc0638a74>] uio_write+0xb4/0x130 [uio] [<ffffffff9706ffa3>] vfs_write+0xc3/0x1f0 [<ffffffff9709349c>] ? fget_light+0xfc/0x510 [<ffffffff97070e2a>] SyS_write+0x8a/0x100 [<ffffffff975ff315>] system_call_fastpath+0x1c/0x21 Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/uio/uio.c16
1 files changed, 6 insertions, 10 deletions
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index fed2d8fa4d4d..4e0cb7cdf739 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -627,6 +627,12 @@ static ssize_t uio_write(struct file *filep, const char __user *buf,
ssize_t retval;
s32 irq_on;
+ if (count != sizeof(s32))
+ return -EINVAL;
+
+ if (copy_from_user(&irq_on, buf, count))
+ return -EFAULT;
+
mutex_lock(&idev->info_lock);
if (!idev->info) {
retval = -EINVAL;
@@ -638,21 +644,11 @@ static ssize_t uio_write(struct file *filep, const char __user *buf,
goto out;
}
- if (count != sizeof(s32)) {
- retval = -EINVAL;
- goto out;
- }
-
if (!idev->info->irqcontrol) {
retval = -ENOSYS;
goto out;
}
- if (copy_from_user(&irq_on, buf, count)) {
- retval = -EFAULT;
- goto out;
- }
-
retval = idev->info->irqcontrol(idev->info, irq_on);
out: