renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-29 15:43:59 +08:00
Code

io_uring: fix imbalanced sqo_mm accounting

Browse Source 
We do the initial accounting of locked_vm and pinned_vm before we have
setup ctx->sqo_mm, which means we can end up having not accounted the
memory at setup time, but still decrement it when we exit. This causes
an imbalance in the accounting.

Setup ctx->sqo_mm earlier in io_uring_create(), before we do the first
accounting of mm->{locked,pinned}_vm. This also unifies the state
grabbing for the ctx, and eliminates a failure case in
io_sq_offload_start().

Fixes: f74441e631 ("io_uring: account locked memory before potential error case")
Reported-by: Robert M. Muncrief <rmuncrief@humanavance.com>
Reported-by: Niklas Schnelle <schnelle@linux.ibm.com>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Tested-by: Robert M. Muncrief <rmuncrief@humanavance.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2020-08-25 07:58:00 -06:00
parent 842163154b
commit 6b7898eb18
1 changed files with 3 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
fs/io_uring.c
View File

@ -7447,9 +7447,6 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
{
int ret;
mmgrab(current->mm);
ctx->sqo_mm = current->mm;
if (ctx->flags & IORING_SETUP_SQPOLL) {
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
@ -7494,10 +7491,6 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
return 0;
err:
io_finish_async(ctx);
if (ctx->sqo_mm) {
mmdrop(ctx->sqo_mm);
ctx->sqo_mm = NULL;
}
return ret;
}
@ -8547,6 +8540,9 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
ctx->user = user;
ctx->creds = get_current_cred();
mmgrab(current->mm);
ctx->sqo_mm = current->mm;
/*
* Account memory _before_ installing the file descriptor. Once
* the descriptor is installed, it can get closed at any time. Also