diff options
| author | Kees Cook <keescook@chromium.org> | 2011-11-17 12:58:07 -0800 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2011-11-17 12:58:07 -0800 |
| commit | f6f8285132907757ef84ef8dae0a1244b8cde6ac (patch) | |
| tree | f3d3b37349e79251cfe16ef0f39e0b4af1a266b1 /include/linux | |
| parent | cfcfc9eca2bcbd26a8e206baeb005b055dbf8e37 (diff) | |
pstore: pass allocated memory region back to caller
The buf_lock cannot be held while populating the inodes, so make the backend
pass forward an allocated and filled buffer instead. This solves the following
backtrace. The effect is that "buf" is only ever used to notify the backends
that something was written to it, and shouldn't be used in the read path.
To replace the buf_lock during the read path, isolate the open/read/close
loop with a separate mutex to maintain serialized access to the backend.
Note that is is up to the pstore backend to cope if the (*write)() path is
called in the middle of the read path.
[ 59.691019] BUG: sleeping function called from invalid context at .../mm/slub.c:847
[ 59.691019] in_atomic(): 0, irqs_disabled(): 1, pid: 1819, name: mount
[ 59.691019] Pid: 1819, comm: mount Not tainted 3.0.8 #1
[ 59.691019] Call Trace:
[ 59.691019] [<810252d5>] __might_sleep+0xc3/0xca
[ 59.691019] [<810a26e6>] kmem_cache_alloc+0x32/0xf3
[ 59.691019] [<810b53ac>] ? __d_lookup_rcu+0x6f/0xf4
[ 59.691019] [<810b68b1>] alloc_inode+0x2a/0x64
[ 59.691019] [<810b6903>] new_inode+0x18/0x43
[ 59.691019] [<81142447>] pstore_get_inode.isra.1+0x11/0x98
[ 59.691019] [<81142623>] pstore_mkfile+0xae/0x26f
[ 59.691019] [<810a2a66>] ? kmem_cache_free+0x19/0xb1
[ 59.691019] [<8116c821>] ? ida_get_new_above+0x140/0x158
[ 59.691019] [<811708ea>] ? __init_rwsem+0x1e/0x2c
[ 59.691019] [<810b67e8>] ? inode_init_always+0x111/0x1b0
[ 59.691019] [<8102127e>] ? should_resched+0xd/0x27
[ 59.691019] [<8137977f>] ? _cond_resched+0xd/0x21
[ 59.691019] [<81142abf>] pstore_get_records+0x52/0xa7
[ 59.691019] [<8114254b>] pstore_fill_super+0x7d/0x91
[ 59.691019] [<810a7ff5>] mount_single+0x46/0x82
[ 59.691019] [<8114231a>] pstore_mount+0x15/0x17
[ 59.691019] [<811424ce>] ? pstore_get_inode.isra.1+0x98/0x98
[ 59.691019] [<810a8199>] mount_fs+0x5a/0x12d
[ 59.691019] [<810b9174>] ? alloc_vfsmnt+0xa4/0x14a
[ 59.691019] [<810b9474>] vfs_kern_mount+0x4f/0x7d
[ 59.691019] [<810b9d7e>] do_kern_mount+0x34/0xb2
[ 59.691019] [<810bb15f>] do_mount+0x5fc/0x64a
[ 59.691019] [<810912fb>] ? strndup_user+0x2e/0x3f
[ 59.691019] [<810bb3cb>] sys_mount+0x66/0x99
[ 59.691019] [<8137b537>] sysenter_do_call+0x12/0x26
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/pstore.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/pstore.h b/include/linux/pstore.h index ea567321ae3..2ca8cde5459 100644 --- a/include/linux/pstore.h +++ b/include/linux/pstore.h @@ -35,10 +35,12 @@ struct pstore_info { spinlock_t buf_lock; /* serialize access to 'buf' */ char *buf; size_t bufsize; + struct mutex read_mutex; /* serialize open/read/close */ int (*open)(struct pstore_info *psi); int (*close)(struct pstore_info *psi); ssize_t (*read)(u64 *id, enum pstore_type_id *type, - struct timespec *time, struct pstore_info *psi); + struct timespec *time, char **buf, + struct pstore_info *psi); int (*write)(enum pstore_type_id type, u64 *id, unsigned int part, size_t size, struct pstore_info *psi); int (*erase)(enum pstore_type_id type, u64 id, |