From: Christoph Hellwig <hch(a)lst.de>
commit 57e95e4670d1126c103305bcf34a9442f49f6d6a upstream.
Don't use a WARN_ON when printing a potentially user triggered
condition. Also don't print the partno when the block device name
already includes it, and use the %pg specifier to simplify printing
the block device name.
Signed-off-by: Christoph Hellwig <hch(a)lst.de>
Reviewed-by: Chaitanya Kulkarni <kch(a)nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn(a)wdc.com>
Link: https://lore.kernel.org/r/20220304180105.409765-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
[the formatted string layout is not changed because struct bio hasn't
got bi_bdev field in stable branches older than 5.15; generic_make_request
is removed as it is unnecessary]
Signed-off-by: Fedor Pchelkin <pchelkin(a)ispras.ru>
---
v1->v2: added backport comment
block/blk-core.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 80f3e729fdd4..4fbf915d9cb0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2179,10 +2179,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
return false;
-
- WARN_ONCE(1,
- "generic_make_request: Trying to write "
- "to read-only block-device %s (partno %d)\n",
+ pr_warn("Trying to write to read-only block-device %s (partno %d)\n",
bio_devname(bio, b), part->partno);
/* Older lvm-tools actually trigger this */
return false;
--
2.34.1
From: Christoph Hellwig <hch(a)lst.de>
commit 57e95e4670d1126c103305bcf34a9442f49f6d6a upstream.
Don't use a WARN_ON when printing a potentially user triggered
condition. Also don't print the partno when the block device name
already includes it, and use the %pg specifier to simplify printing
the block device name.
Signed-off-by: Christoph Hellwig <hch(a)lst.de>
Reviewed-by: Chaitanya Kulkarni <kch(a)nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn(a)wdc.com>
Link: https://lore.kernel.org/r/20220304180105.409765-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
[the formatted string layout is not changed because struct bio hasn't
got bi_bdev field in stable branches older than 5.15; generic_make_request
is removed as it is unnecessary]
Signed-off-by: Fedor Pchelkin <pchelkin(a)ispras.ru>
---
v1->v2: added backport comment
block/blk-core.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 5808baa950c3..030de4fdf9b1 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -793,10 +793,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
return false;
-
- WARN_ONCE(1,
- "generic_make_request: Trying to write "
- "to read-only block-device %s (partno %d)\n",
+ pr_warn("Trying to write to read-only block-device %s (partno %d)\n",
bio_devname(bio, b), part->partno);
/* Older lvm-tools actually trigger this */
return false;
--
2.34.1
From: Christoph Hellwig <hch(a)lst.de>
commit 57e95e4670d1126c103305bcf34a9442f49f6d6a upstream.
Don't use a WARN_ON when printing a potentially user triggered
condition. Also don't print the partno when the block device name
already includes it, and use the %pg specifier to simplify printing
the block device name.
Signed-off-by: Christoph Hellwig <hch(a)lst.de>
Reviewed-by: Chaitanya Kulkarni <kch(a)nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn(a)wdc.com>
Link: https://lore.kernel.org/r/20220304180105.409765-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
[the formatted string layout is not changed because struct bio hasn't
got bi_bdev field in stable branches older than 5.15]
Signed-off-by: Fedor Pchelkin <pchelkin(a)ispras.ru>
---
v1->v2: added backport comment
block/blk-core.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 26664f2a139e..9afb79b322fb 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -700,9 +700,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
return false;
-
- WARN_ONCE(1,
- "Trying to write to read-only block-device %s (partno %d)\n",
+ pr_warn("Trying to write to read-only block-device %s (partno %d)\n",
bio_devname(bio, b), part->partno);
/* Older lvm-tools actually trigger this */
return false;
--
2.30.2
pipe_write cannot be called on notification pipes so
post_one_notification cannot race it.
Locking and second pipe_full check are thus redundant.
This fixes an issue where pipe write could unexpectedly block:
// Assume there is no reader or reader polls and uses FIONREAD ioctl
// to read all the available bytes.
for (int i = 0; i < PIPE_DEF_BUFFERS+1; ++i) {
write(pipe_fd, buf_that_efaults, PAGE_SIZE);
}
// Never reached
Fixes: a194dfe6e6f6 ("pipe: Rearrange sequence in pipe_write() to preallocate slot")
Cc: stable(a)vger.kernel.org
Signed-off-by: Wiktor Garbacz <wiktorg(a)google.com>
---
fs/pipe.c | 35 +++++++++--------------------------
1 file changed, 9 insertions(+), 26 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index 42c7ff41c2db..87356a2823cf 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -501,43 +501,26 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
pipe->tmp_page = page;
}
- /* Allocate a slot in the ring in advance and attach an
- * empty buffer. If we fault or otherwise fail to use
- * it, either the reader will consume it or it'll still
- * be there for the next write.
- */
- spin_lock_irq(&pipe->rd_wait.lock);
-
- head = pipe->head;
- if (pipe_full(head, pipe->tail, pipe->max_usage)) {
- spin_unlock_irq(&pipe->rd_wait.lock);
- continue;
+ copied = copy_page_from_iter(page, 0, PAGE_SIZE, from);
+ if (unlikely(copied < PAGE_SIZE && iov_iter_count(from))) {
+ if (!ret)
+ ret = -EFAULT;
+ break;
}
-
- pipe->head = head + 1;
- spin_unlock_irq(&pipe->rd_wait.lock);
+ ret += copied;
/* Insert it into the buffer array */
- buf = &pipe->bufs[head & mask];
buf->page = page;
buf->ops = &anon_pipe_buf_ops;
buf->offset = 0;
- buf->len = 0;
+ buf->len = copied;
if (is_packetized(filp))
buf->flags = PIPE_BUF_FLAG_PACKET;
else
buf->flags = PIPE_BUF_FLAG_CAN_MERGE;
pipe->tmp_page = NULL;
-
- copied = copy_page_from_iter(page, 0, PAGE_SIZE, from);
- if (unlikely(copied < PAGE_SIZE && iov_iter_count(from))) {
- if (!ret)
- ret = -EFAULT;
- break;
- }
- ret += copied;
- buf->offset = 0;
- buf->len = copied;
+ head++;
+ pipe->head = head;
if (!iov_iter_count(from))
break;
--
2.39.1.456.gfc5497dd1b-goog
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 9d2c7203ffdb846399b82b0660563c89e918c751
Gitweb: https://git.kernel.org/tip/9d2c7203ffdb846399b82b0660563c89e918c751
Author: Joerg Roedel <jroedel(a)suse.de>
AuthorDate: Tue, 31 Jan 2023 09:57:18 +01:00
Committer: Borislav Petkov (AMD) <bp(a)alien8.de>
CommitterDate: Tue, 31 Jan 2023 12:51:19 +01:00
x86/debug: Fix stack recursion caused by wrongly ordered DR7 accesses
In kernels compiled with CONFIG_PARAVIRT=n, the compiler re-orders the
DR7 read in exc_nmi() to happen before the call to sev_es_ist_enter().
This is problematic when running as an SEV-ES guest because in this
environment the DR7 read might cause a #VC exception, and taking #VC
exceptions is not safe in exc_nmi() before sev_es_ist_enter() has run.
The result is stack recursion if the NMI was caused on the #VC IST
stack, because a subsequent #VC exception in the NMI handler will
overwrite the stack frame of the interrupted #VC handler.
As there are no compiler barriers affecting the ordering of DR7
reads/writes, make the accesses to this register volatile, forbidding
the compiler to re-order them.
[ bp: Massage text, make them volatile too, to make sure some
aggressive compiler optimization pass doesn't discard them. ]
Fixes: 315562c9af3d ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler")
Reported-by: Alexey Kardashevskiy <aik(a)amd.com>
Signed-off-by: Joerg Roedel <jroedel(a)suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de>
Cc: stable(a)vger.kernel.org
Link: https://lore.kernel.org/r/20230127035616.508966-1-aik@amd.com
---
arch/x86/include/asm/debugreg.h | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h
index b049d95..ca97442 100644
--- a/arch/x86/include/asm/debugreg.h
+++ b/arch/x86/include/asm/debugreg.h
@@ -39,7 +39,20 @@ static __always_inline unsigned long native_get_debugreg(int regno)
asm("mov %%db6, %0" :"=r" (val));
break;
case 7:
- asm("mov %%db7, %0" :"=r" (val));
+ /*
+ * Apply __FORCE_ORDER to DR7 reads to forbid re-ordering them
+ * with other code.
+ *
+ * This is needed because a DR7 access can cause a #VC exception
+ * when running under SEV-ES. Taking a #VC exception is not a
+ * safe thing to do just anywhere in the entry code and
+ * re-ordering might place the access into an unsafe location.
+ *
+ * This happened in the NMI handler, where the DR7 read was
+ * re-ordered to happen before the call to sev_es_ist_enter(),
+ * causing stack recursion.
+ */
+ asm volatile("mov %%db7, %0" : "=r" (val) : __FORCE_ORDER);
break;
default:
BUG();
@@ -66,7 +79,16 @@ static __always_inline void native_set_debugreg(int regno, unsigned long value)
asm("mov %0, %%db6" ::"r" (value));
break;
case 7:
- asm("mov %0, %%db7" ::"r" (value));
+ /*
+ * Apply __FORCE_ORDER to DR7 writes to forbid re-ordering them
+ * with other code.
+ *
+ * While is didn't happen with a DR7 write (see the DR7 read
+ * comment above which explains where it happened), add the
+ * __FORCE_ORDER here too to avoid similar problems in the
+ * future.
+ */
+ asm volatile("mov %0, %%db7" ::"r" (value), __FORCE_ORDER);
break;
default:
BUG();