[PATCH AUTOSEL 4.9 1/2] epoll: do not insert into poll queues until all sanity checks are done

[PATCH AUTOSEL 4.9 1/2] epoll: do not insert into poll queues until all sanity checks are done

[Sasha Levin]

From: Al Viro <viro@zeniv.linux.org.uk>

[ Upstream commit f8d4f44df056c5b504b0d49683fb7279218fd207 ]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/eventpoll.c | 37 ++++++++++++++++++-------------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 8c40d6652a9a9..d5b68ebbb1631 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1332,6 +1332,22 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
 		RCU_INIT_POINTER(epi->ws, NULL);
 	}
 
+	/* Add the current item to the list of active epoll hook for this file */
+	spin_lock(&tfile->f_lock);
+	list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links);
+	spin_unlock(&tfile->f_lock);
+
+	/*
+	 * Add the current item to the RB tree. All RB tree operations are
+	 * protected by "mtx", and ep_insert() is called with "mtx" held.
+	 */
+	ep_rbtree_insert(ep, epi);
+
+	/* now check if we've created too many backpaths */
+	error = -EINVAL;
+	if (full_check && reverse_path_check())
+		goto error_remove_epi;
+
 	/* Initialize the poll table using the queue callback */
 	epq.epi = epi;
 	init_poll_funcptr(&epq.pt, ep_ptable_queue_proc);
@@ -1354,22 +1370,6 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
 	if (epi->nwait < 0)
 		goto error_unregister;
 
-	/* Add the current item to the list of active epoll hook for this file */
-	spin_lock(&tfile->f_lock);
-	list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links);
-	spin_unlock(&tfile->f_lock);
-
-	/*
-	 * Add the current item to the RB tree. All RB tree operations are
-	 * protected by "mtx", and ep_insert() is called with "mtx" held.
-	 */
-	ep_rbtree_insert(ep, epi);
-
-	/* now check if we've created too many backpaths */
-	error = -EINVAL;
-	if (full_check && reverse_path_check())
-		goto error_remove_epi;
-
 	/* We have to drop the new item inside our item list to keep track of it */
 	spin_lock_irqsave(&ep->lock, flags);
 
@@ -1395,6 +1395,8 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
 
 	return 0;
 
+error_unregister:
+	ep_unregister_pollwait(ep, epi);
 error_remove_epi:
 	spin_lock(&tfile->f_lock);
 	list_del_rcu(&epi->fllink);
@@ -1402,9 +1404,6 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
 
 	rb_erase(&epi->rbn, &ep->rbr);
 
-error_unregister:
-	ep_unregister_pollwait(ep, epi);
-
 	/*
 	 * We need to do this because an event could have been arrived on some
 	 * allocated wait queue. Note that we don't care about the ep->ovflist
-- 
2.25.1

[PATCH AUTOSEL 4.9 2/2] drm/amdgpu: prevent double kfree ttm->sg

[Sasha Levin]

From: Philip Yang <Philip.Yang@amd.com>

[ Upstream commit 1d0e16ac1a9e800598dcfa5b6bc53b704a103390 ]

Set ttm->sg to NULL after kfree, to avoid memory corruption backtrace:

[  420.932812] kernel BUG at
/build/linux-do9eLF/linux-4.15.0/mm/slub.c:295!
[  420.934182] invalid opcode: 0000 [#1] SMP NOPTI
[  420.935445] Modules linked in: xt_conntrack ipt_MASQUERADE
[  420.951332] Hardware name: Dell Inc. PowerEdge R7525/0PYVT1, BIOS
1.5.4 07/09/2020
[  420.952887] RIP: 0010:__slab_free+0x180/0x2d0
[  420.954419] RSP: 0018:ffffbe426291fa60 EFLAGS: 00010246
[  420.955963] RAX: ffff9e29263e9c30 RBX: ffff9e29263e9c30 RCX:
000000018100004b
[  420.957512] RDX: ffff9e29263e9c30 RSI: fffff3d33e98fa40 RDI:
ffff9e297e407a80
[  420.959055] RBP: ffffbe426291fb00 R08: 0000000000000001 R09:
ffffffffc0d39ade
[  420.960587] R10: ffffbe426291fb20 R11: ffff9e49ffdd4000 R12:
ffff9e297e407a80
[  420.962105] R13: fffff3d33e98fa40 R14: ffff9e29263e9c30 R15:
ffff9e2954464fd8
[  420.963611] FS:  00007fa2ea097780(0000) GS:ffff9e297e840000(0000)
knlGS:0000000000000000
[  420.965144] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  420.966663] CR2: 00007f16bfffefb8 CR3: 0000001ff0c62000 CR4:
0000000000340ee0
[  420.968193] Call Trace:
[  420.969703]  ? __page_cache_release+0x3c/0x220
[  420.971294]  ? amdgpu_ttm_tt_unpopulate+0x5e/0x80 [amdgpu]
[  420.972789]  kfree+0x168/0x180
[  420.974353]  ? amdgpu_ttm_tt_set_user_pages+0x64/0xc0 [amdgpu]
[  420.975850]  ? kfree+0x168/0x180
[  420.977403]  amdgpu_ttm_tt_unpopulate+0x5e/0x80 [amdgpu]
[  420.978888]  ttm_tt_unpopulate.part.10+0x53/0x60 [amdttm]
[  420.980357]  ttm_tt_destroy.part.11+0x4f/0x60 [amdttm]
[  420.981814]  ttm_tt_destroy+0x13/0x20 [amdttm]
[  420.983273]  ttm_bo_cleanup_memtype_use+0x36/0x80 [amdttm]
[  420.984725]  ttm_bo_release+0x1c9/0x360 [amdttm]
[  420.986167]  amdttm_bo_put+0x24/0x30 [amdttm]
[  420.987663]  amdgpu_bo_unref+0x1e/0x30 [amdgpu]
[  420.989165]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x9ca/0xb10
[amdgpu]
[  420.990666]  kfd_ioctl_alloc_memory_of_gpu+0xef/0x2c0 [amdgpu]

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 05ff98b43c50f..80c60a62d39ef 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -637,6 +637,7 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm)
 
 release_sg:
 	kfree(ttm->sg);
+	ttm->sg = NULL;
 	return r;
 }
 
-- 
2.25.1