Direct HLT instruction execution causes #VEs for TDX VMs which is routed
to hypervisor via tdvmcall. This process renders HLT instruction
execution inatomic, so any preceding instructions like STI/MOV SS will
end up enabling interrupts before the HLT instruction is routed to the
hypervisor. This creates scenarios where interrupts could land during
HLT instruction emulation without aborting halt operation leading to
idefinite halt wait times.
Commit bfe6ed0c6727 ("x86/tdx: Add HLT support for TDX guests") already
upgraded x86_idle() to invoke tdvmcall to avoid such scenarios, but
it didn't cover pv_native_safe_halt() which can be invoked using
raw_safe_halt() from call sites like acpi_safe_halt().
raw_safe_halt() also returns with interrupts enabled so upgrade
tdx_safe_halt() to enable interrupts by default and ensure that paravirt
safe_halt() executions invoke tdx_safe_halt(). Earlier x86_idle() is now
handled via tdx_idle() which simply invokes tdvmcall while preserving
irq state.
To avoid future call sites which cause HLT instruction emulation with
irqs enabled, add a warn and fail the HLT instruction emulation.
Cc: stable(a)vger.kernel.org
Fixes: bfe6ed0c6727 ("x86/tdx: Add HLT support for TDX guests")
Signed-off-by: Vishal Annapurve <vannapurve(a)google.com>
---
Changes since V1:
1) Addressed comments from Dave H
- Comment regarding adding a check for TDX VMs in halt path is not
resolved in v2, would like feedback around better place to do so,
maybe in pv_native_safe_halt (?).
2) Added a new version of tdx_safe_halt() that will enable interrupts.
3) Previous tdx_safe_halt() implementation is moved to newly introduced
tdx_idle().
V1: https://lore.kernel.org/lkml/Z5l6L3Hen9_Y3SGC@google.com/T/
arch/x86/coco/tdx/tdx.c | 23 ++++++++++++++++++++++-
arch/x86/include/asm/tdx.h | 2 +-
arch/x86/kernel/process.c | 2 +-
3 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 0d9b090b4880..cc2a637dca15 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -14,6 +14,7 @@
#include <asm/ia32.h>
#include <asm/insn.h>
#include <asm/insn-eval.h>
+#include <asm/paravirt_types.h>
#include <asm/pgtable.h>
#include <asm/set_memory.h>
#include <asm/traps.h>
@@ -380,13 +381,18 @@ static int handle_halt(struct ve_info *ve)
{
const bool irq_disabled = irqs_disabled();
+ if (!irq_disabled) {
+ WARN_ONCE(1, "HLT instruction emulation unsafe with irqs enabled\n");
+ return -EIO;
+ }
+
if (__halt(irq_disabled))
return -EIO;
return ve_instr_len(ve);
}
-void __cpuidle tdx_safe_halt(void)
+void __cpuidle tdx_idle(void)
{
const bool irq_disabled = false;
@@ -397,6 +403,12 @@ void __cpuidle tdx_safe_halt(void)
WARN_ONCE(1, "HLT instruction emulation failed\n");
}
+static void __cpuidle tdx_safe_halt(void)
+{
+ tdx_idle();
+ raw_local_irq_enable();
+}
+
static int read_msr(struct pt_regs *regs, struct ve_info *ve)
{
struct tdx_module_args args = {
@@ -1083,6 +1095,15 @@ void __init tdx_early_init(void)
x86_platform.guest.enc_kexec_begin = tdx_kexec_begin;
x86_platform.guest.enc_kexec_finish = tdx_kexec_finish;
+#ifdef CONFIG_PARAVIRT_XXL
+ /*
+ * halt instruction execution is not atomic for TDX VMs as it generates
+ * #VEs, so otherwise "safe" halt invocations which cause interrupts to
+ * get enabled right after halt instruction don't work for TDX VMs.
+ */
+ pv_ops.irq.safe_halt = tdx_safe_halt;
+#endif
+
/*
* TDX intercepts the RDMSR to read the X2APIC ID in the parallel
* bringup low level code. That raises #VE which cannot be handled
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index eba178996d84..dd386500ab1c 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -58,7 +58,7 @@ void tdx_get_ve_info(struct ve_info *ve);
bool tdx_handle_virt_exception(struct pt_regs *regs, struct ve_info *ve);
-void tdx_safe_halt(void);
+void tdx_idle(void);
bool tdx_early_handle_ve(struct pt_regs *regs);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index f63f8fd00a91..4083838fe4a0 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -933,7 +933,7 @@ void __init select_idle_routine(void)
static_call_update(x86_idle, mwait_idle);
} else if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) {
pr_info("using TDX aware idle routine\n");
- static_call_update(x86_idle, tdx_safe_halt);
+ static_call_update(x86_idle, tdx_idle);
} else {
static_call_update(x86_idle, default_idle);
}
--
2.48.1.262.g85cc9f2d1e-goog
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 8d28d0ddb986f56920ac97ae704cc3340a699a30
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020421-exonerate-desecrate-e5ed@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8d28d0ddb986f56920ac97ae704cc3340a699a30 Mon Sep 17 00:00:00 2001
From: Yu Kuai <yukuai3(a)huawei.com>
Date: Fri, 24 Jan 2025 17:20:55 +0800
Subject: [PATCH] md/md-bitmap: Synchronize bitmap_get_stats() with bitmap
lifetime
After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:
Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
<TASK>
md_seq_show+0x2d2/0x5b0
seq_read_iter+0x2b9/0x470
seq_read+0x12f/0x180
proc_reg_read+0x57/0xb0
vfs_read+0xf6/0x380
ksys_read+0x6c/0xf0
do_syscall_64+0x82/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.
Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.
Cc: stable(a)vger.kernel.org # v6.12+
Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com>
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@ora…
Signed-off-by: Yu Kuai <yukuai3(a)huawei.com>
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song(a)kernel.org>
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index ec4ecd96e6b1..23c09d22fcdb 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2355,7 +2355,10 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)
if (!bitmap)
return -ENOENT;
-
+ if (bitmap->mddev->bitmap_info.external)
+ return -ENOENT;
+ if (!bitmap->storage.sb_page) /* no superblock */
+ return -EINVAL;
sb = kmap_local_page(bitmap->storage.sb_page);
stats->sync_size = le64_to_cpu(sb->sync_size);
kunmap_local(sb);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 866015b681af..465ca2af1e6e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8376,6 +8376,10 @@ static int md_seq_show(struct seq_file *seq, void *v)
return 0;
spin_unlock(&all_mddevs_lock);
+
+ /* prevent bitmap to be freed after checking */
+ mutex_lock(&mddev->bitmap_info.mutex);
+
spin_lock(&mddev->lock);
if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
seq_printf(seq, "%s : ", mdname(mddev));
@@ -8451,6 +8455,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "\n");
}
spin_unlock(&mddev->lock);
+ mutex_unlock(&mddev->bitmap_info.mutex);
spin_lock(&all_mddevs_lock);
if (mddev == list_last_entry(&all_mddevs, struct mddev, all_mddevs))
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 8d28d0ddb986f56920ac97ae704cc3340a699a30
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020420-simile-joyride-42b9@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8d28d0ddb986f56920ac97ae704cc3340a699a30 Mon Sep 17 00:00:00 2001
From: Yu Kuai <yukuai3(a)huawei.com>
Date: Fri, 24 Jan 2025 17:20:55 +0800
Subject: [PATCH] md/md-bitmap: Synchronize bitmap_get_stats() with bitmap
lifetime
After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:
Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
<TASK>
md_seq_show+0x2d2/0x5b0
seq_read_iter+0x2b9/0x470
seq_read+0x12f/0x180
proc_reg_read+0x57/0xb0
vfs_read+0xf6/0x380
ksys_read+0x6c/0xf0
do_syscall_64+0x82/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.
Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.
Cc: stable(a)vger.kernel.org # v6.12+
Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com>
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@ora…
Signed-off-by: Yu Kuai <yukuai3(a)huawei.com>
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song(a)kernel.org>
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index ec4ecd96e6b1..23c09d22fcdb 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2355,7 +2355,10 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)
if (!bitmap)
return -ENOENT;
-
+ if (bitmap->mddev->bitmap_info.external)
+ return -ENOENT;
+ if (!bitmap->storage.sb_page) /* no superblock */
+ return -EINVAL;
sb = kmap_local_page(bitmap->storage.sb_page);
stats->sync_size = le64_to_cpu(sb->sync_size);
kunmap_local(sb);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 866015b681af..465ca2af1e6e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8376,6 +8376,10 @@ static int md_seq_show(struct seq_file *seq, void *v)
return 0;
spin_unlock(&all_mddevs_lock);
+
+ /* prevent bitmap to be freed after checking */
+ mutex_lock(&mddev->bitmap_info.mutex);
+
spin_lock(&mddev->lock);
if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
seq_printf(seq, "%s : ", mdname(mddev));
@@ -8451,6 +8455,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "\n");
}
spin_unlock(&mddev->lock);
+ mutex_unlock(&mddev->bitmap_info.mutex);
spin_lock(&all_mddevs_lock);
if (mddev == list_last_entry(&all_mddevs, struct mddev, all_mddevs))
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 8d28d0ddb986f56920ac97ae704cc3340a699a30
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020420-dreamlike-desktop-698c@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8d28d0ddb986f56920ac97ae704cc3340a699a30 Mon Sep 17 00:00:00 2001
From: Yu Kuai <yukuai3(a)huawei.com>
Date: Fri, 24 Jan 2025 17:20:55 +0800
Subject: [PATCH] md/md-bitmap: Synchronize bitmap_get_stats() with bitmap
lifetime
After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:
Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
<TASK>
md_seq_show+0x2d2/0x5b0
seq_read_iter+0x2b9/0x470
seq_read+0x12f/0x180
proc_reg_read+0x57/0xb0
vfs_read+0xf6/0x380
ksys_read+0x6c/0xf0
do_syscall_64+0x82/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.
Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.
Cc: stable(a)vger.kernel.org # v6.12+
Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com>
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@ora…
Signed-off-by: Yu Kuai <yukuai3(a)huawei.com>
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song(a)kernel.org>
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index ec4ecd96e6b1..23c09d22fcdb 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2355,7 +2355,10 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)
if (!bitmap)
return -ENOENT;
-
+ if (bitmap->mddev->bitmap_info.external)
+ return -ENOENT;
+ if (!bitmap->storage.sb_page) /* no superblock */
+ return -EINVAL;
sb = kmap_local_page(bitmap->storage.sb_page);
stats->sync_size = le64_to_cpu(sb->sync_size);
kunmap_local(sb);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 866015b681af..465ca2af1e6e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8376,6 +8376,10 @@ static int md_seq_show(struct seq_file *seq, void *v)
return 0;
spin_unlock(&all_mddevs_lock);
+
+ /* prevent bitmap to be freed after checking */
+ mutex_lock(&mddev->bitmap_info.mutex);
+
spin_lock(&mddev->lock);
if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
seq_printf(seq, "%s : ", mdname(mddev));
@@ -8451,6 +8455,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "\n");
}
spin_unlock(&mddev->lock);
+ mutex_unlock(&mddev->bitmap_info.mutex);
spin_lock(&all_mddevs_lock);
if (mddev == list_last_entry(&all_mddevs, struct mddev, all_mddevs))
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 8d28d0ddb986f56920ac97ae704cc3340a699a30
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020419-arrival-portion-4908@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8d28d0ddb986f56920ac97ae704cc3340a699a30 Mon Sep 17 00:00:00 2001
From: Yu Kuai <yukuai3(a)huawei.com>
Date: Fri, 24 Jan 2025 17:20:55 +0800
Subject: [PATCH] md/md-bitmap: Synchronize bitmap_get_stats() with bitmap
lifetime
After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:
Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
<TASK>
md_seq_show+0x2d2/0x5b0
seq_read_iter+0x2b9/0x470
seq_read+0x12f/0x180
proc_reg_read+0x57/0xb0
vfs_read+0xf6/0x380
ksys_read+0x6c/0xf0
do_syscall_64+0x82/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.
Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.
Cc: stable(a)vger.kernel.org # v6.12+
Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com>
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@ora…
Signed-off-by: Yu Kuai <yukuai3(a)huawei.com>
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song(a)kernel.org>
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index ec4ecd96e6b1..23c09d22fcdb 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2355,7 +2355,10 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)
if (!bitmap)
return -ENOENT;
-
+ if (bitmap->mddev->bitmap_info.external)
+ return -ENOENT;
+ if (!bitmap->storage.sb_page) /* no superblock */
+ return -EINVAL;
sb = kmap_local_page(bitmap->storage.sb_page);
stats->sync_size = le64_to_cpu(sb->sync_size);
kunmap_local(sb);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 866015b681af..465ca2af1e6e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8376,6 +8376,10 @@ static int md_seq_show(struct seq_file *seq, void *v)
return 0;
spin_unlock(&all_mddevs_lock);
+
+ /* prevent bitmap to be freed after checking */
+ mutex_lock(&mddev->bitmap_info.mutex);
+
spin_lock(&mddev->lock);
if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
seq_printf(seq, "%s : ", mdname(mddev));
@@ -8451,6 +8455,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "\n");
}
spin_unlock(&mddev->lock);
+ mutex_unlock(&mddev->bitmap_info.mutex);
spin_lock(&all_mddevs_lock);
if (mddev == list_last_entry(&all_mddevs, struct mddev, all_mddevs))
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 8d28d0ddb986f56920ac97ae704cc3340a699a30
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020419-snippet-epileptic-4280@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8d28d0ddb986f56920ac97ae704cc3340a699a30 Mon Sep 17 00:00:00 2001
From: Yu Kuai <yukuai3(a)huawei.com>
Date: Fri, 24 Jan 2025 17:20:55 +0800
Subject: [PATCH] md/md-bitmap: Synchronize bitmap_get_stats() with bitmap
lifetime
After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:
Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
<TASK>
md_seq_show+0x2d2/0x5b0
seq_read_iter+0x2b9/0x470
seq_read+0x12f/0x180
proc_reg_read+0x57/0xb0
vfs_read+0xf6/0x380
ksys_read+0x6c/0xf0
do_syscall_64+0x82/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.
Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.
Cc: stable(a)vger.kernel.org # v6.12+
Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com>
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@ora…
Signed-off-by: Yu Kuai <yukuai3(a)huawei.com>
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song(a)kernel.org>
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index ec4ecd96e6b1..23c09d22fcdb 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2355,7 +2355,10 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)
if (!bitmap)
return -ENOENT;
-
+ if (bitmap->mddev->bitmap_info.external)
+ return -ENOENT;
+ if (!bitmap->storage.sb_page) /* no superblock */
+ return -EINVAL;
sb = kmap_local_page(bitmap->storage.sb_page);
stats->sync_size = le64_to_cpu(sb->sync_size);
kunmap_local(sb);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 866015b681af..465ca2af1e6e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8376,6 +8376,10 @@ static int md_seq_show(struct seq_file *seq, void *v)
return 0;
spin_unlock(&all_mddevs_lock);
+
+ /* prevent bitmap to be freed after checking */
+ mutex_lock(&mddev->bitmap_info.mutex);
+
spin_lock(&mddev->lock);
if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
seq_printf(seq, "%s : ", mdname(mddev));
@@ -8451,6 +8455,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "\n");
}
spin_unlock(&mddev->lock);
+ mutex_unlock(&mddev->bitmap_info.mutex);
spin_lock(&all_mddevs_lock);
if (mddev == list_last_entry(&all_mddevs, struct mddev, all_mddevs))
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 1378ffec30367233152b7dbf4fa6a25ee98585d1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020458-egotism-espresso-bb20@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 1378ffec30367233152b7dbf4fa6a25ee98585d1 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter(a)linaro.org>
Date: Thu, 17 Oct 2024 23:34:16 +0300
Subject: [PATCH] media: imx-jpeg: Fix potential error pointer dereference in
detach_pm()
The proble is on the first line:
if (jpeg->pd_dev[i] && !pm_runtime_suspended(jpeg->pd_dev[i]))
If jpeg->pd_dev[i] is an error pointer, then passing it to
pm_runtime_suspended() will lead to an Oops. The other conditions
check for both error pointers and NULL, but it would be more clear to
use the IS_ERR_OR_NULL() check for that.
Fixes: fd0af4cd35da ("media: imx-jpeg: Ensure power suppliers be suspended before detach them")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter(a)linaro.org>
Reviewed-by: Ming Qian <ming.qian(a)nxp.com>
Signed-off-by: Hans Verkuil <hverkuil(a)xs4all.nl>
diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
index 7f5fe551179b..1221b309a916 100644
--- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
+++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
@@ -2677,11 +2677,12 @@ static void mxc_jpeg_detach_pm_domains(struct mxc_jpeg_dev *jpeg)
int i;
for (i = 0; i < jpeg->num_domains; i++) {
- if (jpeg->pd_dev[i] && !pm_runtime_suspended(jpeg->pd_dev[i]))
+ if (!IS_ERR_OR_NULL(jpeg->pd_dev[i]) &&
+ !pm_runtime_suspended(jpeg->pd_dev[i]))
pm_runtime_force_suspend(jpeg->pd_dev[i]);
- if (jpeg->pd_link[i] && !IS_ERR(jpeg->pd_link[i]))
+ if (!IS_ERR_OR_NULL(jpeg->pd_link[i]))
device_link_del(jpeg->pd_link[i]);
- if (jpeg->pd_dev[i] && !IS_ERR(jpeg->pd_dev[i]))
+ if (!IS_ERR_OR_NULL(jpeg->pd_dev[i]))
dev_pm_domain_detach(jpeg->pd_dev[i], true);
jpeg->pd_dev[i] = NULL;
jpeg->pd_link[i] = NULL;