This series includes a total of 27 patches, to align minmax.h of
v5.15.y with v6.17-rc6.
The set consists of 24 commits that directly update minmax.h:
1) 92d23c6e9415 ("overflow, tracing: Define the is_signed_type() macro
once")
2) 5efcecd9a3b1 ("minmax: sanity check constant bounds when clamping")
3) 2122e2a4efc2 ("minmax: clamp more efficiently by avoiding extra
comparison")
4) f9bff0e31881 ("minmax: add in_range() macro")
5) c952c748c7a9 ("minmax: Introduce {min,max}_array()")
6) 5e57418a2031 ("minmax: deduplicate __unconst_integer_typeof()")
7) f6e9d38f8eb0 ("minmax: fix header inclusions")
8) d03eba99f5bf ("minmax: allow min()/max()/clamp() if the arguments
have the same signedness.")
9) f4b84b2ff851 ("minmax: fix indentation of __cmp_once() and
__clamp_once()")
10) 4ead534fba42 ("minmax: allow comparisons of 'int' against 'unsigned
char/short'")
11) 867046cc7027 ("minmax: relax check to allow comparison between
unsigned arguments and signed constants")
12) 3a7e02c040b1 ("minmax: avoid overly complicated constant
expressions in VM code")
14) 017fa3e89187 ("minmax: simplify and clarify min_t()/max_t()
implementation")
15) 1a251f52cfdc ("minmax: make generic MIN() and MAX() macros
available everywhere")
18) dc1c8034e31b ("minmax: simplify min()/max()/clamp()
implementation")
19) 22f546873149 ("minmax: improve macro expansion and type
checking")
20) 21b136cc63d2 ("minmax: fix up min3() and max3() too")
21) 71ee9b16251e ("minmax.h: add whitespace around operators and after
commas")
22) 10666e992048 ("minmax.h: update some comments")
23) b280bb27a9f7 ("minmax.h: reduce the #define expansion of min(),
max() and clamp()")
24) a5743f32baec ("minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi
test in clamp()")
25) c3939872ee4a ("minmax.h: move all the clamp() definitions after the
min/max() ones")
26) 495bba17cdf9 ("minmax.h: simplify the variants of clamp()")
27) 2b97aaf74ed5 ("minmax.h: remove some #defines that are only
expanded once")
2 prerequisite commits that adjust users of MIN and MAX macros (to
prevent compilation issues):
13) 4477b39c32fd ("minmax: add a few more MIN_T/MAX_T users")
17) cb04e8b1d2f2 ("minmax: don't use max() in situations that want a C
constant expression")
1 additional commit introduced to resolve a build failures during the
backport:
16) lib: zstd: drop local MIN/MAX macros in favor of generic ones
The primary motivation is to bring in commit (8).
In mainline, this change allows min()/max()/clamp() to accept mixed
argument types when both share the same signedness.
Backported patches to v5.10.y that use such forms trigger compiler
warnings, which in turn cause build failures when -Werror is enabled.
Originaly I aligned 5.10.y to 5.15.y, but David Laight commented that I
need to pick up the later changes (from Linus) as well.
Andy Shevchenko (2):
minmax: deduplicate __unconst_integer_typeof()
minmax: fix header inclusions
Bart Van Assche (1):
overflow, tracing: Define the is_signed_type() macro once
David Laight (11):
minmax: allow min()/max()/clamp() if the arguments have the same
signedness.
minmax: fix indentation of __cmp_once() and __clamp_once()
minmax: allow comparisons of 'int' against 'unsigned char/short'
minmax: relax check to allow comparison between unsigned arguments and
signed constants
minmax.h: add whitespace around operators and after commas
minmax.h: update some comments
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: simplify the variants of clamp()
minmax.h: remove some #defines that are only expanded once
Eliav Farber (1):
lib: zstd: drop local MIN/MAX macros in favor of generic ones
Herve Codina (1):
minmax: Introduce {min,max}_array()
Jason A. Donenfeld (2):
minmax: sanity check constant bounds when clamping
minmax: clamp more efficiently by avoiding extra comparison
Linus Torvalds (8):
minmax: avoid overly complicated constant expressions in VM code
minmax: add a few more MIN_T/MAX_T users
minmax: simplify and clarify min_t()/max_t() implementation
minmax: make generic MIN() and MAX() macros available everywhere
minmax: don't use max() in situations that want a C constant
expression
minmax: simplify min()/max()/clamp() implementation
minmax: improve macro expansion and type checking
minmax: fix up min3() and max3() too
Matthew Wilcox (Oracle) (1):
minmax: add in_range() macro
arch/arm/mm/pageattr.c | 6 +-
arch/um/drivers/mconsole_user.c | 2 +
arch/x86/mm/pgtable.c | 2 +-
drivers/edac/sb_edac.c | 4 +-
drivers/edac/skx_common.h | 1 -
.../drm/amd/display/modules/hdcp/hdcp_ddc.c | 2 +
.../drm/amd/pm/powerplay/hwmgr/ppevvmath.h | 14 +-
.../drm/arm/display/include/malidp_utils.h | 2 +-
.../display/komeda/komeda_pipeline_state.c | 24 +-
drivers/gpu/drm/drm_color_mgmt.c | 2 +-
drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 6 -
drivers/gpu/drm/radeon/evergreen_cs.c | 2 +
drivers/hwmon/adt7475.c | 24 +-
drivers/input/touchscreen/cyttsp4_core.c | 2 +-
drivers/md/dm-integrity.c | 2 +-
drivers/media/dvb-frontends/stv0367_priv.h | 3 +
.../net/ethernet/chelsio/cxgb3/cxgb3_main.c | 18 +-
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
drivers/net/fjes/fjes_main.c | 4 +-
drivers/nfc/pn544/i2c.c | 2 -
drivers/platform/x86/sony-laptop.c | 1 -
drivers/scsi/isci/init.c | 6 +-
.../pci/hive_isp_css_include/math_support.h | 5 -
fs/btrfs/misc.h | 2 -
fs/btrfs/tree-checker.c | 2 +-
fs/ext2/balloc.c | 2 -
fs/ext4/ext4.h | 2 -
fs/ufs/util.h | 6 -
include/linux/compiler.h | 15 +
include/linux/minmax.h | 267 ++++++++++++++----
include/linux/overflow.h | 1 -
include/linux/trace_events.h | 2 -
kernel/trace/preemptirq_delay_test.c | 2 -
lib/btree.c | 1 -
lib/decompress_unlzma.c | 2 +
lib/logic_pio.c | 3 -
lib/vsprintf.c | 2 +-
lib/zstd/zstd_internal.h | 2 -
mm/zsmalloc.c | 1 -
net/ipv4/proc.c | 2 +-
net/ipv6/proc.c | 2 +-
net/netfilter/nf_nat_core.c | 6 +-
net/tipc/core.h | 2 +-
net/tipc/link.c | 10 +-
44 files changed, 306 insertions(+), 164 deletions(-)
--
2.47.3
This series backports 7 patches to update minmax.h in the 6.12.y branch,
aligning it with v6.17-rc7.
The ultimate goal is to synchronize all longterm branches so that they
include the full set of minmax.h changes.
The key motivation is to bring in commit d03eba99f5bf ("minmax: allow
min()/max()/clamp() if the arguments have the same signedness"), which
is missing in older kernels.
In mainline, this change enables min()/max()/clamp() to accept mixed
argument types, provided both have the same signedness. Without it,
backported patches that use these forms may trigger compiler warnings,
which escalate to build failures when -Werror is enabled.
David Laight (7):
minmax.h: add whitespace around operators and after commas
minmax.h: update some comments
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: simplify the variants of clamp()
minmax.h: remove some #defines that are only expanded once
include/linux/minmax.h | 205 +++++++++++++++++++----------------------
1 file changed, 95 insertions(+), 110 deletions(-)
--
2.47.3
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 cba4262a19afae21665ee242b3404bcede5a94d7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091431-craftily-size-46c6@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From cba4262a19afae21665ee242b3404bcede5a94d7 Mon Sep 17 00:00:00 2001
From: K Prateek Nayak <kprateek.nayak(a)amd.com>
Date: Mon, 1 Sep 2025 17:04:15 +0000
Subject: [PATCH] x86/cpu/topology: Always try cpu_parse_topology_ext() on
AMD/Hygon
Support for parsing the topology on AMD/Hygon processors using CPUID leaf 0xb
was added in
3986a0a805e6 ("x86/CPU/AMD: Derive CPU topology from CPUID function 0xB when available").
In an effort to keep all the topology parsing bits in one place, this commit
also introduced a pseudo dependency on the TOPOEXT feature to parse the CPUID
leaf 0xb.
The TOPOEXT feature (CPUID 0x80000001 ECX[22]) advertises the support for
Cache Properties leaf 0x8000001d and the CPUID leaf 0x8000001e EAX for
"Extended APIC ID" however support for 0xb was introduced alongside the x2APIC
support not only on AMD [1], but also historically on x86 [2].
Similar to 0xb, the support for extended CPU topology leaf 0x80000026 too does
not depend on the TOPOEXT feature.
The support for these leaves is expected to be confirmed by ensuring
leaf <= {extended_}cpuid_level
and then parsing the level 0 of the respective leaf to confirm EBX[15:0]
(LogProcAtThisLevel) is non-zero as stated in the definition of
"CPUID_Fn0000000B_EAX_x00 [Extended Topology Enumeration]
(Core::X86::Cpuid::ExtTopEnumEax0)" in Processor Programming Reference (PPR)
for AMD Family 19h Model 01h Rev B1 Vol1 [3] Sec. 2.1.15.1 "CPUID Instruction
Functions".
This has not been a problem on baremetal platforms since support for TOPOEXT
(Fam 0x15 and later) predates the support for CPUID leaf 0xb (Fam 0x17[Zen2]
and later), however, for AMD guests on QEMU, the "x2apic" feature can be
enabled independent of the "topoext" feature where QEMU expects topology and
the initial APICID to be parsed using the CPUID leaf 0xb (especially when
number of cores > 255) which is populated independent of the "topoext" feature
flag.
Unconditionally call cpu_parse_topology_ext() on AMD and Hygon processors to
first parse the topology using the XTOPOLOGY leaves (0x80000026 / 0xb) before
using the TOPOEXT leaf (0x8000001e).
While at it, break down the single large comment in parse_topology_amd() to
better highlight the purpose of each CPUID leaf.
Fixes: 3986a0a805e6 ("x86/CPU/AMD: Derive CPU topology from CPUID function 0xB when available")
Suggested-by: Naveen N Rao (AMD) <naveen(a)kernel.org>
Signed-off-by: K Prateek Nayak <kprateek.nayak(a)amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de>
Cc: stable(a)vger.kernel.org # Only v6.9 and above; depends on x86 topology rewrite
Link: https://lore.kernel.org/lkml/1529686927-7665-1-git-send-email-suravee.suthi… [1]
Link: https://lore.kernel.org/lkml/20080818181435.523309000@linux-os.sc.intel.com/ [2]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 [3]
diff --git a/arch/x86/kernel/cpu/topology_amd.c b/arch/x86/kernel/cpu/topology_amd.c
index 827dd0dbb6e9..c79ebbb639cb 100644
--- a/arch/x86/kernel/cpu/topology_amd.c
+++ b/arch/x86/kernel/cpu/topology_amd.c
@@ -175,27 +175,30 @@ static void topoext_fixup(struct topo_scan *tscan)
static void parse_topology_amd(struct topo_scan *tscan)
{
- bool has_topoext = false;
-
/*
- * If the extended topology leaf 0x8000_001e is available
- * try to get SMT, CORE, TILE, and DIE shifts from extended
+ * Try to get SMT, CORE, TILE, and DIE shifts from extended
* CPUID leaf 0x8000_0026 on supported processors first. If
* extended CPUID leaf 0x8000_0026 is not supported, try to
- * get SMT and CORE shift from leaf 0xb first, then try to
- * get the CORE shift from leaf 0x8000_0008.
+ * get SMT and CORE shift from leaf 0xb. If either leaf is
+ * available, cpu_parse_topology_ext() will return true.
*/
- if (cpu_feature_enabled(X86_FEATURE_TOPOEXT))
- has_topoext = cpu_parse_topology_ext(tscan);
+ bool has_xtopology = cpu_parse_topology_ext(tscan);
if (cpu_feature_enabled(X86_FEATURE_AMD_HTR_CORES))
tscan->c->topo.cpu_type = cpuid_ebx(0x80000026);
- if (!has_topoext && !parse_8000_0008(tscan))
+ /*
+ * If XTOPOLOGY leaves (0x26/0xb) are not available, try to
+ * get the CORE shift from leaf 0x8000_0008 first.
+ */
+ if (!has_xtopology && !parse_8000_0008(tscan))
return;
- /* Prefer leaf 0x8000001e if available */
- if (parse_8000_001e(tscan, has_topoext))
+ /*
+ * Prefer leaf 0x8000001e if available to get the SMT shift and
+ * the initial APIC ID if XTOPOLOGY leaves are not available.
+ */
+ if (parse_8000_001e(tscan, has_xtopology))
return;
/* Try the NODEID MSR */
The mei_ace driver contains a device reference count leak in
mei_ace_setup_dev_link() where device_find_child_by_name() increases
the reference count of the found device but this reference is not
properly decreased in the success path. Add put_device() in
mei_ace_setup_dev_link() and delete put_device() in mei_ace_remove(),
which ensures that the reference count of the device is correctly
managed regardless of whether the probe is successful or fails.
Found by code review.
Cc: stable(a)vger.kernel.org
Fixes: 78876f71b3e9 ("media: pci: intel: ivsc: Add ACE submodule")
Signed-off-by: Ma Ke <make24(a)iscas.ac.cn>
---
Changes in v2:
- modified the put_device() operations and the patch title as suggestions.
---
drivers/media/pci/intel/ivsc/mei_ace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/pci/intel/ivsc/mei_ace.c b/drivers/media/pci/intel/ivsc/mei_ace.c
index 98310b8511b1..bb57656fc85a 100644
--- a/drivers/media/pci/intel/ivsc/mei_ace.c
+++ b/drivers/media/pci/intel/ivsc/mei_ace.c
@@ -420,6 +420,7 @@ static int mei_ace_setup_dev_link(struct mei_ace *ace)
goto err_put;
}
+ put_device(csi_dev);
ace->csi_dev = csi_dev;
return 0;
@@ -522,7 +523,6 @@ static void mei_ace_remove(struct mei_cl_device *cldev)
cancel_work_sync(&ace->work);
device_link_del(ace->csi_link);
- put_device(ace->csi_dev);
pm_runtime_disable(&cldev->dev);
pm_runtime_set_suspended(&cldev->dev);
--
2.17.1
This series backports 15 patches to update minmax.h in the 6.6.y branch,
aligning it with v6.17-rc7.
The ultimate goal is to synchronize all longterm branches so that they
include the full set of minmax.h changes.
The key motivation is to bring in commit d03eba99f5bf ("minmax: allow
min()/max()/clamp() if the arguments have the same signedness"), which
is missing in older kernels.
In mainline, this change enables min()/max()/clamp() to accept mixed
argument types, provided both have the same signedness. Without it,
backported patches that use these forms may trigger compiler warnings,
which escalate to build failures when -Werror is enabled.
David Laight (7):
minmax.h: add whitespace around operators and after commas
minmax.h: update some comments
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: simplify the variants of clamp()
minmax.h: remove some #defines that are only expanded once
Linus Torvalds (8):
minmax: avoid overly complicated constant expressions in VM code
minmax: simplify and clarify min_t()/max_t() implementation
minmax: add a few more MIN_T/MAX_T users
minmax: make generic MIN() and MAX() macros available everywhere
minmax: simplify min()/max()/clamp() implementation
minmax: don't use max() in situations that want a C constant
expression
minmax: improve macro expansion and type checking
minmax: fix up min3() and max3() too
arch/um/drivers/mconsole_user.c | 2 +
arch/x86/mm/pgtable.c | 2 +-
drivers/edac/sb_edac.c | 4 +-
drivers/edac/skx_common.h | 1 -
.../drm/amd/display/modules/hdcp/hdcp_ddc.c | 2 +
.../drm/amd/pm/powerplay/hwmgr/ppevvmath.h | 14 +-
drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c | 2 +-
drivers/gpu/drm/drm_color_mgmt.c | 2 +-
drivers/gpu/drm/radeon/evergreen_cs.c | 2 +
drivers/hwmon/adt7475.c | 24 +-
drivers/input/touchscreen/cyttsp4_core.c | 2 +-
drivers/irqchip/irq-sun6i-r.c | 2 +-
drivers/md/dm-integrity.c | 6 +-
drivers/media/dvb-frontends/stv0367_priv.h | 3 +
.../net/can/usb/etas_es58x/es58x_devlink.c | 2 +-
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
drivers/net/fjes/fjes_main.c | 4 +-
drivers/nfc/pn544/i2c.c | 2 -
drivers/platform/x86/sony-laptop.c | 1 -
drivers/scsi/isci/init.c | 6 +-
.../pci/hive_isp_css_include/math_support.h | 5 -
fs/btrfs/tree-checker.c | 2 +-
include/linux/compiler.h | 9 +
include/linux/minmax.h | 228 +++++++++++-------
include/linux/pageblock-flags.h | 2 +-
kernel/trace/preemptirq_delay_test.c | 2 -
lib/btree.c | 1 -
lib/decompress_unlzma.c | 2 +
lib/vsprintf.c | 2 +-
mm/zsmalloc.c | 2 -
net/ipv4/proc.c | 2 +-
net/ipv6/proc.c | 2 +-
tools/testing/selftests/mm/mremap_test.c | 2 +
tools/testing/selftests/seccomp/seccomp_bpf.c | 2 +
34 files changed, 202 insertions(+), 146 deletions(-)
--
2.47.3
When PAGEMAP_SCAN ioctl invoked with vec_len = 0 reaches
pagemap_scan_backout_range(), kernel panics with null-ptr-deref:
[ 44.936808] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[ 44.937797] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[ 44.938391] CPU: 1 UID: 0 PID: 2480 Comm: reproducer Not tainted 6.17.0-rc6 #22 PREEMPT(none)
[ 44.939062] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 44.939935] RIP: 0010:pagemap_scan_thp_entry.isra.0+0x741/0xa80
<snip registers, unreliable trace>
[ 44.946828] Call Trace:
[ 44.947030] <TASK>
[ 44.949219] pagemap_scan_pmd_entry+0xec/0xfa0
[ 44.952593] walk_pmd_range.isra.0+0x302/0x910
[ 44.954069] walk_pud_range.isra.0+0x419/0x790
[ 44.954427] walk_p4d_range+0x41e/0x620
[ 44.954743] walk_pgd_range+0x31e/0x630
[ 44.955057] __walk_page_range+0x160/0x670
[ 44.956883] walk_page_range_mm+0x408/0x980
[ 44.958677] walk_page_range+0x66/0x90
[ 44.958984] do_pagemap_scan+0x28d/0x9c0
[ 44.961833] do_pagemap_cmd+0x59/0x80
[ 44.962484] __x64_sys_ioctl+0x18d/0x210
[ 44.962804] do_syscall_64+0x5b/0x290
[ 44.963111] entry_SYSCALL_64_after_hwframe+0x76/0x7e
vec_len = 0 in pagemap_scan_init_bounce_buffer() means no buffers are
allocated and p->vec_buf remains set to NULL.
This breaks an assumption made later in pagemap_scan_backout_range(),
that page_region is always allocated for p->vec_buf_index.
Fix it by explicitly checking p->vec_buf for NULL before dereferencing.
Other sites that might run into same deref-issue are already (directly
or transitively) protected by checking p->vec_buf.
Note:
From PAGEMAP_SCAN man page, it seems vec_len = 0 is valid when no output
is requested and it's only the side effects caller is interested in,
hence it passes check in pagemap_scan_get_args().
This issue was found by syzkaller.
Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Jakub Acs <acsjakub(a)amazon.de>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: David Hildenbrand <david(a)redhat.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com>
Cc: Jinjiang Tu <tujinjiang(a)huawei.com>
Cc: Suren Baghdasaryan <surenb(a)google.com>
Cc: Penglei Jiang <superman.xpt(a)gmail.com>
Cc: Mark Brown <broonie(a)kernel.org>
Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com>
Cc: Ryan Roberts <ryan.roberts(a)arm.com>
Cc: Andrei Vagin <avagin(a)gmail.com>
Cc: "Michał Mirosław" <mirq-linux(a)rere.qmqm.pl>
Cc: Stephen Rothwell <sfr(a)canb.auug.org.au>
Cc: Muhammad Usama Anjum <usama.anjum(a)collabora.com>
Cc: linux-kernel(a)vger.kernel.org
Cc: linux-fsdevel(a)vger.kernel.org
Cc: stable(a)vger.kernel.org
---
v1 -> v2: check p->vec_buf instead of cur_buf
v2 -> v3: fix commit title
v1: https://lore.kernel.org/all/20250919142106.43527-1-acsjakub@amazon.de/
v2: https://lore.kernel.org/all/20250922081713.77303-1-acsjakub@amazon.de/
fs/proc/task_mmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 29cca0e6d0ff..b26ae556b446 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -2417,6 +2417,9 @@ static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
{
struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index];
+ if (!p->vec_buf)
+ return;
+
if (cur_buf->start != addr)
cur_buf->end = addr;
else
--
2.47.3
Amazon Web Services Development Center Germany GmbH
Tamara-Danz-Str. 13
10243 Berlin
Geschaeftsfuehrung: Christian Schlaeger
Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B
Sitz: Berlin
Ust-ID: DE 365 538 597
When PAGEMAP_SCAN ioctl invoked with vec_len = 0 reaches
pagemap_scan_backout_range(), kernel panics with null-ptr-deref:
[ 44.936808] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[ 44.937797] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[ 44.938391] CPU: 1 UID: 0 PID: 2480 Comm: reproducer Not tainted 6.17.0-rc6 #22 PREEMPT(none)
[ 44.939062] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 44.939935] RIP: 0010:pagemap_scan_thp_entry.isra.0+0x741/0xa80
<snip registers, unreliable trace>
[ 44.946828] Call Trace:
[ 44.947030] <TASK>
[ 44.949219] pagemap_scan_pmd_entry+0xec/0xfa0
[ 44.952593] walk_pmd_range.isra.0+0x302/0x910
[ 44.954069] walk_pud_range.isra.0+0x419/0x790
[ 44.954427] walk_p4d_range+0x41e/0x620
[ 44.954743] walk_pgd_range+0x31e/0x630
[ 44.955057] __walk_page_range+0x160/0x670
[ 44.956883] walk_page_range_mm+0x408/0x980
[ 44.958677] walk_page_range+0x66/0x90
[ 44.958984] do_pagemap_scan+0x28d/0x9c0
[ 44.961833] do_pagemap_cmd+0x59/0x80
[ 44.962484] __x64_sys_ioctl+0x18d/0x210
[ 44.962804] do_syscall_64+0x5b/0x290
[ 44.963111] entry_SYSCALL_64_after_hwframe+0x76/0x7e
vec_len = 0 in pagemap_scan_init_bounce_buffer() means no buffers are
allocated and p->vec_buf remains set to NULL.
This breaks an assumption made later in pagemap_scan_backout_range(),
that page_region is always allocated for p->vec_buf_index.
Fix it by explicitly checking cur_buf for NULL before dereferencing.
Other sites that might run into same deref-issue are already (directly
or transitively) protected by checking p->vec_buf.
Note:
From PAGEMAP_SCAN man page, it seems vec_len = 0 is valid when no output
is requested and it's only the side effects caller is interested in,
hence it passes check in pagemap_scan_get_args().
This issue was found by syzkaller.
Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: David Hildenbrand <david(a)redhat.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com>
Cc: Jinjiang Tu <tujinjiang(a)huawei.com>
Cc: Suren Baghdasaryan <surenb(a)google.com>
Cc: Penglei Jiang <superman.xpt(a)gmail.com>
Cc: Mark Brown <broonie(a)kernel.org>
Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com>
Cc: Ryan Roberts <ryan.roberts(a)arm.com>
Cc: Andrei Vagin <avagin(a)gmail.com>
Cc: "Michał Mirosław" <mirq-linux(a)rere.qmqm.pl>
Cc: Stephen Rothwell <sfr(a)canb.auug.org.au>
Cc: Muhammad Usama Anjum <usama.anjum(a)collabora.com>
linux-kernel(a)vger.kernel.org
linux-fsdevel(a)vger.kernel.org
Cc: stable(a)vger.kernel.org
Signed-off-by: Jakub Acs <acsjakub(a)amazon.de>
---
fs/proc/task_mmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 29cca0e6d0ff..8c10a8135e74 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -2417,6 +2417,9 @@ static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
{
struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index];
+ if (!cur_buf)
+ return;
+
if (cur_buf->start != addr)
cur_buf->end = addr;
else
--
2.47.3
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