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From 584f54de25634442d9c9c390385ff0c50bd9d7f4 Mon Sep 17 00:00:00 2001 |
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From: =?UTF-8?q?Javier=20Gonz=C3=A1lez?= <javier@javigon.com> |
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Date: Tue, 9 Oct 2018 13:12:07 +0200 |
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Subject: [PATCH 014/145] lightnvm: pblk: fix race on sysfs line state |
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MIME-Version: 1.0 |
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Content-Type: text/plain; charset=UTF-8 |
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Content-Transfer-Encoding: 8bit |
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[ Upstream commit 44cdbdc657b23f75736eca3e88b781f009104363 ] |
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|
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pblk exposes a sysfs interface that represents its internal state. Part |
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of this state is the map bitmap for the current open line, which should |
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be protected by the line lock to avoid a race when freeing the line |
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metadata. Currently, it is not. |
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|
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This patch makes sure that the line state is consistent and NULL |
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bitmap pointers are not dereferenced. |
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|
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Signed-off-by: Javier González <javier@cnexlabs.com> |
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Signed-off-by: Matias Bjørling <mb@lightnvm.io> |
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Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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Signed-off-by: Sasha Levin <sashal@kernel.org> |
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--- |
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drivers/lightnvm/pblk-core.c | 5 +++-- |
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drivers/lightnvm/pblk-sysfs.c | 8 +++++++- |
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2 files changed, 10 insertions(+), 3 deletions(-) |
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|
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diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c |
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index 00984b486fea..2940cdc87af1 100644 |
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--- a/drivers/lightnvm/pblk-core.c |
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+++ b/drivers/lightnvm/pblk-core.c |
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@@ -1539,13 +1539,14 @@ struct pblk_line *pblk_line_replace_data(struct pblk *pblk) |
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struct pblk_line *cur, *new = NULL; |
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unsigned int left_seblks; |
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|
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- cur = l_mg->data_line; |
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new = l_mg->data_next; |
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if (!new) |
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goto out; |
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- l_mg->data_line = new; |
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|
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spin_lock(&l_mg->free_lock); |
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+ cur = l_mg->data_line; |
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+ l_mg->data_line = new; |
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+ |
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pblk_line_setup_metadata(new, l_mg, &pblk->lm); |
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spin_unlock(&l_mg->free_lock); |
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|
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diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c |
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index 9fc3dfa168b4..8d2ed510c04b 100644 |
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--- a/drivers/lightnvm/pblk-sysfs.c |
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+++ b/drivers/lightnvm/pblk-sysfs.c |
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@@ -262,8 +262,14 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page) |
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sec_in_line = l_mg->data_line->sec_in_line; |
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meta_weight = bitmap_weight(&l_mg->meta_bitmap, |
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PBLK_DATA_LINES); |
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- map_weight = bitmap_weight(l_mg->data_line->map_bitmap, |
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+ |
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+ spin_lock(&l_mg->data_line->lock); |
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+ if (l_mg->data_line->map_bitmap) |
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+ map_weight = bitmap_weight(l_mg->data_line->map_bitmap, |
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lm->sec_per_line); |
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+ else |
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+ map_weight = 0; |
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+ spin_unlock(&l_mg->data_line->lock); |
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} |
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spin_unlock(&l_mg->free_lock); |
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|
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-- |
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2.19.1 |
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