Alexander Shishkin 614662016d stm class: Lose the protocol driver when dropping its reference ... commit 0a8f72fafb upstream. Commit c7fd62bc69 ("stm class: Introduce framing protocol drivers") forgot to tear down the link between an stm device and its protocol driver when policy is removed. This leads to an invalid pointer reference if one tries to write to an stm device after the policy has been removed and the protocol driver module unloaded, leading to the below splat: > BUG: unable to handle page fault for address: ffffffffc0737068 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 3d780f067 P4D 3d780f067 PUD 3d7811067 PMD 492781067 PTE 0 > Oops: 0000 [#1] SMP NOPTI > CPU: 1 PID: 26122 Comm: cat Not tainted 5.4.0-rc5+ #1 > RIP: 0010:stm_output_free+0x40/0xc0 [stm_core] > Call Trace: > stm_char_release+0x3e/0x70 [stm_core] > __fput+0xc6/0x260 > ____fput+0xe/0x10 > task_work_run+0x9d/0xc0 > exit_to_usermode_loop+0x103/0x110 > do_syscall_64+0x19d/0x1e0 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by tearing down the link from an stm device to its protocol driver when the policy involving that driver is removed. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Fixes: c7fd62bc69 ("stm class: Introduce framing protocol drivers") Reported-by: Ammy Yi <ammy.yi@intel.com> Tested-by: Ammy Yi <ammy.yi@intel.com> CC: stable@vger.kernel.org # v4.20+ Link: https://lore.kernel.org/r/20191114064201.43089-2-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-12-17 19:56:41 +01:00
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Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	stm class: Add MIPI SyS-T protocol support	2018-10-11 12:12:54 +02:00
console.c	stm class: Add SPDX GPL-2.0 header to replace GPLv2 boilerplate	2018-03-28 18:47:17 +03:00
core.c	LED updates for 5.4-rc1	2019-09-17 18:40:42 -07:00
dummy_stm.c	stm class: Make dummy's master/channel ranges configurable	2018-03-28 18:47:18 +03:00
ftrace.c	coresight: Moving framework and drivers to SPDX identifier	2018-05-14 16:19:59 +02:00
heartbeat.c	stm class: heartbeat: Fix whitespace	2018-10-11 12:12:55 +02:00
p_basic.c	stm class: Factor out default framing protocol	2018-10-11 12:12:54 +02:00
p_sys-t.c	stm class: p_sys-t: Add support for CLOCKSYNC packets	2018-10-11 12:12:54 +02:00
policy.c	stm class: Lose the protocol driver when dropping its reference	2019-12-17 19:56:41 +01:00
stm.h	stm class: Add a helper for writing data packets	2018-10-11 12:12:54 +02:00