NothingOSS/android_kernel_msm-6.1_nothing_sm7635
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

powerpc/watchpoint: Disable pagefaults when getting user instruction

Browse source 
[ Upstream commit 3241f260eb830d27d09cc604690ec24533fdb433 ]

This is called in an atomic context, so is not allowed to sleep if a
user page needs to be faulted in and has nowhere it can be deferred to.
The pagefault_disabled() function is documented as preventing user
access methods from sleeping.

In practice the page will be mapped in nearly always because we are
reading the instruction that just triggered the watchpoint trap.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230829063457.54157-3-bgray@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Benjamin Gray 2023-08-29 16:34:56 +10:00 • committed by Greg Kroah-Hartman
parent 16722418cb
commit 3632e9fd82
1 changed files with 6 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

7
arch/powerpc/kernel/hw_breakpoint_constraints.c
View file

@ -131,8 +131,13 @@ void wp_get_instr_detail(struct pt_regs *regs, ppc_inst_t *instr,
int *type, int *size, unsigned long *ea)
{
struct instruction_op op;
int err;
if (__get_user_instr(*instr, (void __user *)regs->nip))
pagefault_disable();
err = __get_user_instr(*instr, (void __user *)regs->nip);
pagefault_enable();
if (err)
return;
analyse_instr(&op, regs, *instr);