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From: Christian Brauner <brauner@kernel.org>
To: linux-fsdevel@vger.kernel.org
Cc: Jacob Lalonde <jalalonde@meta.com>,
	Josef Bacik <josef@toxicpanda.com>,  Jann Horn <jannh@google.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	 Jan Kara <jack@suse.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	 David Hildenbrand <david@kernel.org>,
	Lorenzo Stoakes <ljs@kernel.org>,
	 "Liam R. Howlett" <liam@infradead.org>,
	Vlastimil Babka <vbabka@kernel.org>,
	 Mike Rapoport <rppt@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	 Michal Hocko <mhocko@suse.com>,
	Omar Sandoval <osandov@osandov.com>,
	 Jacob Lalonde <jalalonde@fb.com>, Shuah Khan <shuah@kernel.org>,
	 linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	 linux-kselftest@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	 "Christian Brauner (Amutable)" <brauner@kernel.org>
Subject: [PATCH 2/6] tools: sync coredump.h header
Date: Fri, 21 Aug 2026 13:52:03 +0200	[thread overview]
Message-ID: <20260821-work-coredump-filter-v1-2-91f9a73ef03e@kernel.org> (raw)
In-Reply-To: <20260821-work-coredump-filter-v1-0-91f9a73ef03e@kernel.org>

Sync the headers for the selftests.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 tools/include/uapi/linux/coredump.h | 70 +++++++++++++++++++++++++++++++++++--
 1 file changed, 68 insertions(+), 2 deletions(-)

diff --git a/tools/include/uapi/linux/coredump.h b/tools/include/uapi/linux/coredump.h
index f3771861ca48..6d0c53b534ea 100644
--- a/tools/include/uapi/linux/coredump.h
+++ b/tools/include/uapi/linux/coredump.h
@@ -16,6 +16,9 @@
  *                    requires COREDUMP_KERNEL
  * @COREDUMP_SPARSE: describe the holes in the coredump as zero records
  *                   instead of transferring them; requires COREDUMP_RECORDS
+ * @COREDUMP_MEMORY_TYPES: dump the memory types in
+ *                          coredump_ack->memory_types instead of the ones
+ *                          the task selected; requires COREDUMP_KERNEL
  */
 enum {
 	COREDUMP_KERNEL		= (1ULL << 0),
@@ -24,6 +27,37 @@ enum {
 	COREDUMP_WAIT		= (1ULL << 3),
 	COREDUMP_RECORDS	= (1ULL << 4),
 	COREDUMP_SPARSE		= (1ULL << 5),
+	COREDUMP_MEMORY_TYPES	= (1ULL << 6),
+};
+
+/**
+ * coredump memory types
+ * @COREDUMP_MEMORY_ANON_PRIVATE: anonymous private memory
+ * @COREDUMP_MEMORY_ANON_SHARED: anonymous shared memory
+ * @COREDUMP_MEMORY_FILE_PRIVATE: file-backed private memory
+ * @COREDUMP_MEMORY_FILE_SHARED: file-backed shared memory
+ * @COREDUMP_MEMORY_ELF_HEADERS: the first page of a file-backed private
+ *                               mapping that starts an ELF file
+ * @COREDUMP_MEMORY_HUGETLB_PRIVATE: hugetlb private memory
+ * @COREDUMP_MEMORY_HUGETLB_SHARED: hugetlb shared memory
+ * @COREDUMP_MEMORY_DAX_PRIVATE: DAX private memory
+ * @COREDUMP_MEMORY_DAX_SHARED: DAX shared memory
+ *
+ * A bitmask of memory types a coredump may request to be included. New
+ * memory type bits must ensure that they do not steal memory from an
+ * existing one so a coredump server will continue to get the same
+ * coredumps even if a new bit is introduced.
+ */
+enum {
+	COREDUMP_MEMORY_ANON_PRIVATE	= (1ULL << 0),
+	COREDUMP_MEMORY_ANON_SHARED	= (1ULL << 1),
+	COREDUMP_MEMORY_FILE_PRIVATE	= (1ULL << 2),
+	COREDUMP_MEMORY_FILE_SHARED	= (1ULL << 3),
+	COREDUMP_MEMORY_ELF_HEADERS	= (1ULL << 4),
+	COREDUMP_MEMORY_HUGETLB_PRIVATE	= (1ULL << 5),
+	COREDUMP_MEMORY_HUGETLB_SHARED	= (1ULL << 6),
+	COREDUMP_MEMORY_DAX_PRIVATE	= (1ULL << 7),
+	COREDUMP_MEMORY_DAX_SHARED	= (1ULL << 8),
 };
 
 /**
@@ -31,6 +65,8 @@ enum {
  * @size: size of struct coredump_req
  * @size_ack: known size of struct coredump_ack on this kernel
  * @mask: supported features
+ * @memory_types: the memory types the task selected
+ * @memory_types_mask: the memory types this kernel knows
  *
  * When a coredump happens the kernel will connect to the coredump
  * socket and send a coredump request to the coredump server. The @size
@@ -49,15 +85,27 @@ enum {
  * struct coredump_ack the kernel knows. Userspace may only send up to
  * coredump_req->size_ack bytes to the kernel and must set
  * coredump_ack->size accordingly.
+ *
+ * @memory_types is set to the default memory types that are included in
+ * the coredump. This can be overridden by raising bits in
+ * coredump_ack->memory_types.
+ *
+ * @memory_types_mask contains a bitmask of all memory types the kernel
+ * knows about. A coredump server may only raise bits in
+ * coredump_ack->memory_types that are raised in
+ * coredump_req->memory_types_mask.
  */
 struct coredump_req {
 	__u32 size;
 	__u32 size_ack;
 	__u64 mask;
+	__u64 memory_types;
+	__u64 memory_types_mask;
 };
 
 enum {
 	COREDUMP_REQ_SIZE_VER0 = 16U, /* size of first published struct */
+	COREDUMP_REQ_SIZE_VER1 = 32U, /* memory_types and memory_types_mask added */
 };
 
 /**
@@ -65,6 +113,8 @@ enum {
  * @size: size of the struct
  * @spare: unused
  * @mask: features kernel is supposed to use
+ * @memory_types: memory types to dump, only with COREDUMP_MEMORY_TYPES
+ *                 in @mask
  *
  * The @size member must be set to the size of struct coredump_ack. It
  * may never exceed what the kernel returned in coredump_req->size_ack
@@ -74,15 +124,30 @@ enum {
  * The @mask member must be set to the features the coredump server
  * wants the kernel to use. Only bits the kernel returned in
  * coredump_req->mask may be set.
+ *
+ * If COREDUMP_MEMORY_TYPES is raised in @mask the kernel dumps the
+ * memory types set in the @memory_types mask. Zero is valid and dumps
+ * no memory apart from the mappings that are always dumped.
+ *
+ * Note that memory a task excluded via MADV_DONTDUMP is always left
+ * out. A coredump server wanting to add or drop memory types instead of
+ * outright replacing it should simply copy coredump_req->memory_types
+ * and then mask off or raise types as needed.
+ *
+ * Note that @memory_types must be zero if COREDUMP_MEMORY_TYPES isn't
+ * raised. COREDUMP_MEMORY_TYPES requires COREDUMP_KERNEL and an ack of
+ * at least COREDUMP_ACK_SIZE_VER1 bytes.
  */
 struct coredump_ack {
 	__u32 size;
 	__u32 spare;
 	__u64 mask;
+	__u64 memory_types;
 };
 
 enum {
 	COREDUMP_ACK_SIZE_VER0 = 16U, /* size of first published struct */
+	COREDUMP_ACK_SIZE_VER1 = 24U, /* memory_types added */
 };
 
 /**
@@ -90,11 +155,12 @@ enum {
  *
  * The kernel will place a single byte on the coredump socket. The
  * markers notify userspace whether the coredump ack succeeded or
- * failed.
+ * failed. After any marker other than COREDUMP_MARK_REQACK the kernel
+ * closes the connection and no coredump is generated.
  *
  * @COREDUMP_MARK_MINSIZE: the provided coredump_ack size was too small
  * @COREDUMP_MARK_MAXSIZE: the provided coredump_ack size was too big
- * @COREDUMP_MARK_UNSUPPORTED: the provided coredump_ack mask was invalid
+ * @COREDUMP_MARK_UNSUPPORTED: the provided coredump_ack mask or memory types were invalid
  * @COREDUMP_MARK_CONFLICTING: the provided coredump_ack mask has conflicting options
  * @COREDUMP_MARK_REQACK: the coredump request and ack was successful
  * @__COREDUMP_MARK_MAX: the maximum coredump mark value

-- 
2.53.0



  parent reply	other threads:[~2026-08-21 11:52 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-21 11:52 [PATCH 0/6] coredump: select memory types per request Christian Brauner
2026-08-21 11:52 ` [PATCH 1/6] coredump: select memory types to include Christian Brauner
2026-08-21 11:52 ` Christian Brauner [this message]
2026-08-21 11:52 ` [PATCH 3/6] selftests/coredump: simplify the refusal tests Christian Brauner
2026-08-21 11:52 ` [PATCH 4/6] selftests/coredump: test COREDUMP_MEMORY_TYPES Christian Brauner
2026-08-21 11:52 ` [PATCH 5/6] selftests/coredump: improve coredump size negotiation tests Christian Brauner
2026-08-21 11:52 ` [PATCH 6/6] selftests/coredump: test failed handshakes Christian Brauner

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