Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
3f167e1921
ipv4_pdp_add() is called in RCU read-side critical section.
So GFP_KERNEL should not be used in the function.
This patch make ipv4_pdp_add() to use GFP_ATOMIC instead of GFP_KERNEL.
Test commands:
gtp-link add gtp1 &
gtp-tunnel add gtp1 v1 100 200 1.1.1.1 2.2.2.2
Splat looks like:
[ 130.618881] =============================
[ 130.626382] WARNING: suspicious RCU usage
[ 130.626994] 5.2.0-rc6+ #50 Not tainted
[ 130.627622] -----------------------------
[ 130.628223] ./include/linux/rcupdate.h:266 Illegal context switch in RCU read-side critical section!
[ 130.629684]
[ 130.629684] other info that might help us debug this:
[ 130.629684]
[ 130.631022]
[ 130.631022] rcu_scheduler_active = 2, debug_locks = 1
[ 130.632136] 4 locks held by gtp-tunnel/1025:
[ 130.632925] #0: 000000002b93c8b7 (cb_lock){++++}, at: genl_rcv+0x15/0x40
[ 130.634159] #1: 00000000f17bc999 (genl_mutex){+.+.}, at: genl_rcv_msg+0xfb/0x130
[ 130.635487] #2: 00000000c644ed8e (rtnl_mutex){+.+.}, at: gtp_genl_new_pdp+0x18c/0x1150 [gtp]
[ 130.636936] #3: 0000000007a1cde7 (rcu_read_lock){....}, at: gtp_genl_new_pdp+0x187/0x1150 [gtp]
[ 130.638348]
[ 130.638348] stack backtrace:
[ 130.639062] CPU: 1 PID: 1025 Comm: gtp-tunnel Not tainted 5.2.0-rc6+ #50
[ 130.641318] Call Trace:
[ 130.641707] dump_stack+0x7c/0xbb
[ 130.642252] ___might_sleep+0x2c0/0x3b0
[ 130.642862] kmem_cache_alloc_trace+0x1cd/0x2b0
[ 130.643591] gtp_genl_new_pdp+0x6c5/0x1150 [gtp]
[ 130.644371] genl_family_rcv_msg+0x63a/0x1030
[ 130.645074] ? mutex_lock_io_nested+0x1090/0x1090
[ 130.645845] ? genl_unregister_family+0x630/0x630
[ 130.646592] ? debug_show_all_locks+0x2d0/0x2d0
[ 130.647293] ? check_flags.part.40+0x440/0x440
[ 130.648099] genl_rcv_msg+0xa3/0x130
[ ... ]
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
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.