From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Pavel Begunkov <asml.silence@gmail.com>,
Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>,
linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org
Subject: [PATCH AUTOSEL 5.10 26/31] io_uring: remove racy overflow list fast checks
Date: Wed, 30 Dec 2020 08:03:08 -0500 [thread overview]
Message-ID: <20201230130314.3636961-26-sashal@kernel.org> (raw)
In-Reply-To: <20201230130314.3636961-1-sashal@kernel.org>
From: Pavel Begunkov <asml.silence@gmail.com>
[ Upstream commit 9cd2be519d05ee78876d55e8e902b7125f78b74f ]
list_empty_careful() is not racy only if some conditions are met, i.e.
no re-adds after del_init. io_cqring_overflow_flush() does list_move(),
so it's actually racy.
Remove those checks, we have ->cq_check_overflow for the fast path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/io_uring.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 86dac2b2e2763..4b3dbe588d111 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1632,8 +1632,6 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
LIST_HEAD(list);
if (!force) {
- if (list_empty_careful(&ctx->cq_overflow_list))
- return true;
if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) ==
rings->cq_ring_entries))
return false;
@@ -6548,8 +6546,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
/* if we have a backlog and couldn't flush it all, return BUSY */
if (test_bit(0, &ctx->sq_check_overflow)) {
- if (!list_empty(&ctx->cq_overflow_list) &&
- !io_cqring_overflow_flush(ctx, false, NULL, NULL))
+ if (!io_cqring_overflow_flush(ctx, false, NULL, NULL))
return -EBUSY;
}
--
2.27.0
next prev parent reply other threads:[~2020-12-30 13:08 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-30 13:02 [PATCH AUTOSEL 5.10 01/31] ARM: 9014/2: Replace string mem* functions for KASan Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 02/31] rtc: sun6i: Fix memleak in sun6i_rtc_clk_init Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 03/31] module: set MODULE_STATE_GOING state when a module fails to load Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 04/31] quota: Don't overflow quota file offsets Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 05/31] rtc: pl031: fix resource leak in pl031_probe Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 06/31] powerpc: sysdev: add missing iounmap() on error in mpic_msgr_probe() Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 07/31] i3c master: fix missing destroy_workqueue() on error in i3c_master_register Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 08/31] reiserfs: add check for an invalid ih_entry_count Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 09/31] NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 10/31] f2fs: Handle casefolding with Encryption Sasha Levin
2020-12-30 18:01 ` [f2fs-dev] " Eric Biggers
2021-01-04 14:20 ` Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 11/31] f2fs: avoid race condition for shrinker count Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 12/31] f2fs: fix race of pending_pages in decompression Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 13/31] module: delay kobject uevent until after module init call Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 14/31] powerpc/64: irq replay remove decrementer overflow check Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 15/31] f2fs: fix shift-out-of-bounds in sanity_check_raw_super() Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 16/31] fs/namespace.c: WARN if mnt_count has become negative Sasha Levin
2020-12-30 13:02 ` [PATCH AUTOSEL 5.10 17/31] watchdog: rti-wdt: fix reference leak in rti_wdt_probe Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 18/31] um: random: Register random as hwrng-core device Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 19/31] um: ubd: Submit all data segments atomically Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 20/31] um: allocate a guard page to helper threads Sasha Levin
2020-12-30 14:48 ` Johannes Berg
2021-01-04 14:21 ` Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 21/31] NFSv4.2: Don't error when exiting early on a READ_PLUS buffer overflow Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 22/31] ceph: fix inode refcount leak when ceph_fill_inode on non-I_NEW inode fails Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 23/31] drm/amd/display: updated wm table for Renoir Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 24/31] tick/sched: Remove bogus boot "safety" check Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 25/31] s390: always clear kernel stack backchain before calling functions Sasha Levin
2020-12-30 13:03 ` Sasha Levin [this message]
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 27/31] ext4: check for invalid block size early when mounting a file system Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 28/31] ALSA: pcm: Clear the full allocated memory at hw_params Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 29/31] dm verity: skip verity work if I/O error when system is shutting down Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 30/31] ext4: avoid s_mb_prefetch to be zero in individual scenarios Sasha Levin
2020-12-30 13:03 ` [PATCH AUTOSEL 5.10 31/31] device-dax: Fix range release Sasha Levin
2020-12-30 14:18 ` [PATCH AUTOSEL 5.10 01/31] ARM: 9014/2: Replace string mem* functions for KASan Ahmad Fatoum
2021-01-04 14:29 ` Sasha Levin
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