From f1f76f865b5f66db5b5c7f2d19874f2bb9b43b8d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 16 Dec 2009 21:31:33 +0000 Subject: devtmpfs: Convert dirlock to a mutex devtmpfs has a rw_lock dirlock which serializes delete_path and create_path. This code was obviously never tested with the usual set of debugging facilities enabled. In the dirlock held sections the code calls: - vfs functions which take mutexes - kmalloc(, GFP_KERNEL) In both code pathes the might sleep warning triggers and spams dmesg. Convert the rw_lock to a mutex. There is no reason why this needs to be a rwlock. Signed-off-by: Thomas Gleixner Cc: Kay Sievers Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/base/devtmpfs.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'drivers/base/devtmpfs.c') diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 50375bb8e51..278371c7bf5 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -32,7 +32,7 @@ static int dev_mount = 1; static int dev_mount; #endif -static rwlock_t dirlock; +static DEFINE_MUTEX(dirlock); static int __init mount_param(char *str) { @@ -93,7 +93,7 @@ static int create_path(const char *nodepath) { int err; - read_lock(&dirlock); + mutex_lock(&dirlock); err = dev_mkdir(nodepath, 0755); if (err == -ENOENT) { char *path; @@ -117,7 +117,7 @@ static int create_path(const char *nodepath) } kfree(path); } - read_unlock(&dirlock); + mutex_unlock(&dirlock); return err; } @@ -229,7 +229,7 @@ static int delete_path(const char *nodepath) if (!path) return -ENOMEM; - write_lock(&dirlock); + mutex_lock(&dirlock); for (;;) { char *base; @@ -241,7 +241,7 @@ static int delete_path(const char *nodepath) if (err) break; } - write_unlock(&dirlock); + mutex_unlock(&dirlock); kfree(path); return err; @@ -352,8 +352,6 @@ int __init devtmpfs_init(void) int err; struct vfsmount *mnt; - rwlock_init(&dirlock); - err = register_filesystem(&dev_fs_type); if (err) { printk(KERN_ERR "devtmpfs: unable to register devtmpfs " -- cgit From 8042273801059884da2d53bbca34575d090b6f4e Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Tue, 22 Dec 2009 22:25:16 +0100 Subject: devtmpfs: unlock mutex in case of string allocation error Reported-by: Kirill A. Shutemov Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- drivers/base/devtmpfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'drivers/base/devtmpfs.c') diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 278371c7bf5..090dd485130 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -101,8 +101,10 @@ static int create_path(const char *nodepath) /* parent directories do not exist, create them */ path = kstrdup(nodepath, GFP_KERNEL); - if (!path) - return -ENOMEM; + if (!path) { + err = -ENOMEM; + goto out; + } s = path; for (;;) { s = strchr(s, '/'); @@ -117,6 +119,7 @@ static int create_path(const char *nodepath) } kfree(path); } +out: mutex_unlock(&dirlock); return err; } -- cgit From f776c5ec4690b21b3668ad5956774a22c86f541a Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 18 Jan 2010 14:36:12 +0100 Subject: driver-core: fix devtmpfs crash on s390 On Mon, Jan 18, 2010 at 05:26:20PM +0530, Sachin Sant wrote: > Hello Heiko, > > Today while trying to boot next-20100118 i came across > the following Oops : > > Brought up 4 CPUs > Unable to handle kernel pointer dereference at virtual kernel address 0000000000 > 543000 > Oops: 0004 #1 SMP > Modules linked in: > CPU: 0 Not tainted 2.6.33-rc4-autotest-next-20100118-5-default #1 > Process swapper (pid: 1, task: 00000000fd792038, ksp: 00000000fd797a30) > Krnl PSW : 0704200180000000 00000000001eb0b8 (shmem_parse_options+0xc0/0x328) > R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3 > Krnl GPRS: 000000000054388a 000000000000003d 0000000000543836 000000000000003d > 0000000000000000 0000000000483f28 0000000000536112 00000000fd797d00 > 00000000fd4ba100 0000000000000100 0000000000483978 0000000000543832 > 0000000000000000 0000000000465958 00000000001eb0b0 00000000fd797c58 > Krnl Code: 00000000001eb0aa: c0e5000994f1 brasl %r14,31da8c > 00000000001eb0b0: b9020022 ltgr %r2,%r2 > 00000000001eb0b4: a784010b brc 8,1eb2ca > >00000000001eb0b8: 92002000 mvi 0(%r2),0 > 00000000001eb0bc: a7080000 lhi %r0,0 > 00000000001eb0c0: 41902001 la %r9,1(%r2) > 00000000001eb0c4: b9040016 lgr %r1,%r6 > 00000000001eb0c8: b904002b lgr %r2,%r11 > Call Trace: > (<00000000fd797c50> 0xfd797c50) > <00000000001eb5da> shmem_fill_super+0x13a/0x25c > <0000000000228cfa> get_sb_single+0xbe/0xdc > <000000000034ffc0> dev_get_sb+0x2c/0x38 > <000000000066c602> devtmpfs_init+0x46/0xc0 > <000000000066c53e> driver_init+0x22/0x60 > <000000000064d40a> kernel_init+0x24e/0x3d0 > <000000000010a7ea> kernel_thread_starter+0x6/0xc > <000000000010a7e4> kernel_thread_starter+0x0/0xc > > I never tried to boot a kernel with DEVTMPFS enabled on a s390 box. > So am wondering if this is supported or not ? If you think this > is supported i will send a mail to community on this. There is nothing arch specific to devtmpfs. This part crashes because the kernel tries to modify the data read-only section which is write protected on s390. Signed-off-by: Heiko Carstens Acked-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- drivers/base/devtmpfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/base/devtmpfs.c') diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 090dd485130..42ae452b36b 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -354,6 +354,7 @@ int __init devtmpfs_init(void) { int err; struct vfsmount *mnt; + char options[] = "mode=0755"; err = register_filesystem(&dev_fs_type); if (err) { @@ -362,7 +363,7 @@ int __init devtmpfs_init(void) return err; } - mnt = kern_mount_data(&dev_fs_type, "mode=0755"); + mnt = kern_mount_data(&dev_fs_type, options); if (IS_ERR(mnt)) { err = PTR_ERR(mnt); printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err); -- cgit