As reported by Richard Sharpe, an attempt to use fuse_notify_inval_entry() triggers complains about scheduling while atomic:
> Jun 23 11:53:24 localhost kernel: BUG: scheduling while atomic: fuse.hf/13976/0x10000001 This happens because fuse_notify_inval_entry() attempts to allocate memory with GFP_KERNEL, holding "struct fuse_copy_state" mapped by kmap_atomic(). The patch fixes the problem for fuse_notify_inval_entry() and other notifiers by unmapping fuse_copy_state before allocations and remapping it again afterwards. Reported-by: Richard Sharpe <[email protected]> Signed-off-by: Maxim Patlasov <[email protected]> --- fs/fuse/dev.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 098f97b..502aa1d 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -755,6 +755,22 @@ static int fuse_copy_fill(struct fuse_copy_state *cs) return lock_request(cs->fc, cs->req); } +static void fuse_copy_unmap(struct fuse_copy_state *cs) +{ + cs->buf = (void *)(cs->buf - cs->mapaddr); + kunmap_atomic(cs->mapaddr); +} + +static void fuse_copy_remap(struct fuse_copy_state *cs) +{ + if (cs->currbuf) + cs->mapaddr = kmap_atomic(cs->currbuf->page); + else + cs->mapaddr = kmap_atomic(cs->pg); + + cs->buf = (unsigned long)cs->buf + cs->mapaddr; +} + /* Do as much copy to/from userspace buffer as we can */ static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) { @@ -1431,7 +1447,9 @@ static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, char *buf; struct qstr name; + fuse_copy_unmap(cs); buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); + fuse_copy_remap(cs); if (!buf) goto err; @@ -1482,7 +1500,9 @@ static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, char *buf; struct qstr name; + fuse_copy_unmap(cs); buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); + fuse_copy_remap(cs); if (!buf) goto err; @@ -1554,6 +1574,7 @@ static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, nodeid = outarg.nodeid; + fuse_copy_unmap(cs); down_read(&fc->killsb); err = -ENOENT; @@ -1586,7 +1607,9 @@ static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, goto out_iput; this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset); + fuse_copy_remap(cs); err = fuse_copy_page(cs, &page, offset, this_num, 0); + fuse_copy_unmap(cs); if (!err && offset == 0 && (this_num == PAGE_CACHE_SIZE || file_size == end)) SetPageUptodate(page); @@ -1607,6 +1630,7 @@ out_iput: iput(inode); out_up_killsb: up_read(&fc->killsb); + fuse_copy_remap(cs); out_finish: fuse_copy_finish(cs); return err; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
