a11148e6fc
syzbot found WARNING in rds_rdma_extra_size [1] when RDS_CMSG_RDMA_ARGS control message is passed with user-controlled 0x40001 bytes of args->nr_local, causing order >= MAX_ORDER condition. The exact value 0x40001 can be checked with UIO_MAXIOV which is 0x400. So for kcalloc() 0x400 iovecs with sizeof(struct rds_iovec) = 0x10 is the closest limit, with 0x10 leftover. Same condition is currently done in rds_cmsg_rdma_args(). [1] WARNING: mm/page_alloc.c:5011 [..] Call Trace: alloc_pages_current+0x18c/0x2a0 mm/mempolicy.c:2267 alloc_pages include/linux/gfp.h:547 [inline] kmalloc_order+0x2e/0xb0 mm/slab_common.c:837 kmalloc_order_trace+0x14/0x120 mm/slab_common.c:853 kmalloc_array include/linux/slab.h:592 [inline] kcalloc include/linux/slab.h:621 [inline] rds_rdma_extra_size+0xb2/0x3b0 net/rds/rdma.c:568 rds_rm_size net/rds/send.c:928 [inline] Reported-by: syzbot+1bd2b07f93745fa38425@syzkaller.appspotmail.com Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Link: https://lore.kernel.org/r/20210201203233.1324704-1-snovitoll@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.