dump: do not dump non-existent guest memory

PATCH In review Cornelia Huck 5 participants 9 messages Sep 11, 2017 – Sep 14, 2017

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Cornelia Huck

author

2017-09-11 13:26 UTC #0 lore raw

PATCH 1/1 dump: do not dump non-existent guest memory

It does not really make sense to dump memory that is not there.

Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.

New behaviour is:

(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump

Signed-off-by Cornelia Huck <[email protected]>

---

Another unmaintained file. Joy. cc:ing some more-or-less random folks.

---
 dump.c | 6 ++++++
 1 file changed, 6 insertions(+)

dump.c +6 -0

index a79773d0f7..d2093e141b 100644
@@ -1536,6 +1536,12 @@ static void dump_init(DumpState *s, int fd, bool has_format,
     fprintf(stderr, "DUMP: total memory to dump: %lu\n", s->total_size);
 #endif
 
+    /* it does not make sense to dump non-existent memory */
+    if (!s->total_size) {
+        error_setg(errp, "dump: no guest memory to dump");
+        goto cleanup;
+    }
+
     s->start = get_start_block(s);
     if (s->start == -1) {
         error_setg(errp, QERR_INVALID_PARAMETER, "begin");

Signature · 1 line

2.13.5

Laurent Vivier

Tested-by Reviewed-by on v1 1/1

2017-09-11 13:45 UTC #1 lore raw

Quoted 29 lines · Cornelia Huck

It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.
New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump
Signed-off-by Cornelia Huck <[email protected]>
---
Another unmaintained file. Joy. cc:ing some more-or-less random folks.
---
 dump.c | 6 ++++++
 1 file changed, 6 insertions(+)
dump.c +0 -0
index a79773d0f7..d2093e141b 100644
@@ -1536,6 +1536,12 @@ static void dump_init(DumpState *s, int fd, bool has_format,
     fprintf(stderr, "DUMP: total memory to dump: %lu\n", s->total_size);
 #endif

dump.c static void dump_init(DumpState *s, int fd, bool has_format, · line 1547

Quoted 10 lines

dump.c +6 -0

 
+    /* it does not make sense to dump non-existent memory */
+    if (!s->total_size) {
+        error_setg(errp, "dump: no guest memory to dump");
+        goto cleanup;
+    }
+
     s->start = get_start_block(s);
     if (s->start == -1) {
         error_setg(errp, QERR_INVALID_PARAMETER, "begin");

We need to update test-hmp, as with this change dump-guest-memory will do nothing with none machine, as by default memory size is 0 MB (I'm working on that)

Tested-by Laurent Vivier <[email protected]>

Reviewed-by Laurent Vivier <[email protected]>

Greg Kurz

Reviewed-by on v1 1/1

2017-09-11 14:02 UTC #2 lore raw

In reply to Cornelia Huck

Quoted 5 lines · On Mon, 11 Sep 2017 15:26:27 +0200 Cornelia Huck <[email protected]> wrote:

It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.

Quoted 8 lines

New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump
Signed-off-by Cornelia Huck <[email protected]>

Reviewed-by Greg Kurz <[email protected]>

Quoted 25 lines

---

Another unmaintained file. Joy. cc:ing some more-or-less random folks.

---
 dump.c | 6 ++++++
 1 file changed, 6 insertions(+)

dump.c +6 -0

index a79773d0f7..d2093e141b 100644
@@ -1536,6 +1536,12 @@ static void dump_init(DumpState *s, int fd, bool has_format,
     fprintf(stderr, "DUMP: total memory to dump: %lu\n", s->total_size);
 #endif
 
+    /* it does not make sense to dump non-existent memory */
+    if (!s->total_size) {
+        error_setg(errp, "dump: no guest memory to dump");
+        goto cleanup;
+    }
+
     s->start = get_start_block(s);
     if (s->start == -1) {
         error_setg(errp, QERR_INVALID_PARAMETER, "begin");

Peter Xu

Reviewed-by on v1 1/1

2017-09-12 02:30 UTC #3 lore raw

In reply to Cornelia Huck

Quoted 5 lines · Cornelia Huck

It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.

Quoted 8 lines

New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump
Signed-off-by Cornelia Huck <[email protected]>

Reviewed-by Peter Xu <[email protected]>

Quoted 28 lines

---

Another unmaintained file. Joy. cc:ing some more-or-less random folks.

---
 dump.c | 6 ++++++
 1 file changed, 6 insertions(+)

dump.c +6 -0

index a79773d0f7..d2093e141b 100644
@@ -1536,6 +1536,12 @@ static void dump_init(DumpState *s, int fd, bool has_format,
     fprintf(stderr, "DUMP: total memory to dump: %lu\n", s->total_size);
 #endif
 
+    /* it does not make sense to dump non-existent memory */
+    if (!s->total_size) {
+        error_setg(errp, "dump: no guest memory to dump");
+        goto cleanup;
+    }
+
     s->start = get_start_block(s);
     if (s->start == -1) {
         error_setg(errp, QERR_INVALID_PARAMETER, "begin");

Signature · 1 line

2.13.5

Signature · 1 line

Peter Xu

Peter Xu

2017-09-12 03:33 UTC #4 lore raw

In reply to Cornelia Huck

Quoted 12 lines · Cornelia Huck

It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.
New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump

Quoted 4 lines

Signed-off-by Cornelia Huck <[email protected]>
---
Another unmaintained file. Joy. cc:ing some more-or-less random folks.

I thought Marc-André had proposed to be the maintainer? But indeed I didn't see the line in maintainer file.

Anyway, if anyone think I am ok to maintain this single file (considering that I haven't posted patches on it for 2 years, and I haven't been working on any kind of maintainer job), please let me know. I'm glad to start with it (or with Marc-André).

Thanks,

Signature · 1 line

Peter Xu

Marc-André Lureau

2017-09-12 10:17 UTC #5 lore raw

Hi Peter

Quoted 18 lines · Peter Xu

Quoted 12 lines · Cornelia Huck
It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.
New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump
Quoted 4 lines
Signed-off-by Cornelia Huck <[email protected]>
---
Another unmaintained file. Joy. cc:ing some more-or-less random folks.

Quoted 8 lines

I thought Marc-André had proposed to be the maintainer? But indeed I didn't see the line in maintainer file.
Anyway, if anyone think I am ok to maintain this single file (considering that I haven't posted patches on it for 2 years, and I haven't been working on any kind of maintainer job), please let me know. I'm glad to start with it (or with Marc-André).

That would be great!
thanks

Signature · 1 line

Marc-André Lureau

Peter Xu

2017-09-13 06:12 UTC #6 lore raw

Quoted 24 lines · Marc-André Lureau

Hi Peter
Quoted 21 lines · Peter Xu
Quoted 12 lines · Cornelia Huck
It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.
New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump
Quoted 4 lines
Signed-off-by Cornelia Huck <[email protected]>
---
Another unmaintained file. Joy. cc:ing some more-or-less random folks.
I thought Marc-André had proposed to be the maintainer? But indeed I didn't see the line in maintainer file.

Quoted 8 lines

Quoted 5 lines
Anyway, if anyone think I am ok to maintain this single file (considering that I haven't posted patches on it for 2 years, and I haven't been working on any kind of maintainer job), please let me know. I'm glad to start with it (or with Marc-André).
That would be great!
thanks

Let me try to draft a maintainer file change for this, to see whether there are objections. Thanks!

Signature · 1 line

Peter Xu

Cornelia Huck

author

2017-09-13 07:58 UTC #7 lore raw

In reply to Marc-André Lureau

Quoted 24 lines · On Tue, 12 Sep 2017 12:17:51 +0200 Marc-André Lureau…

Hi Peter
Quoted 21 lines · Peter Xu
Quoted 12 lines · Cornelia Huck
It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.
New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump
Quoted 4 lines
Signed-off-by Cornelia Huck <[email protected]>
---
Another unmaintained file. Joy. cc:ing some more-or-less random folks.
I thought Marc-André had proposed to be the maintainer? But indeed I didn't see the line in maintainer file.

Quoted 8 lines

Quoted 5 lines
Anyway, if anyone think I am ok to maintain this single file (considering that I haven't posted patches on it for 2 years, and I haven't been working on any kind of maintainer job), please let me know. I'm glad to start with it (or with Marc-André).
That would be great!
thanks

Now on to the most important question: Will you merge this patch? :)

(It should probably go together with "tests/hmp: test "none" machine with memory".)

Peter Xu

2017-09-14 05:40 UTC #8 lore raw

Quoted 33 lines · Cornelia Huck

Quoted 30 lines · On Tue, 12 Sep 2017 12:17:51 +0200 Marc-André Lureau…
Hi Peter
Quoted 26 lines · Peter Xu
Quoted 12 lines · Cornelia Huck
It does not really make sense to dump memory that is not there.
Moreover, that fixes a segmentation fault when calling dump-guest-memory with no filter for a machine with no memory defined.
New behaviour is:
(qemu) dump-guest-memory /dev/null
dump: no guest memory to dump
(qemu) dump-guest-memory /dev/null 0 4096
dump: no guest memory to dump
Quoted 4 lines
Signed-off-by Cornelia Huck <[email protected]>
---
Another unmaintained file. Joy. cc:ing some more-or-less random folks.
I thought Marc-André had proposed to be the maintainer? But indeed I didn't see the line in maintainer file.
Anyway, if anyone think I am ok to maintain this single file (considering that I haven't posted patches on it for 2 years, and I haven't been working on any kind of maintainer job), please let me know. I'm glad to start with it (or with Marc-André).

Quoted 7 lines

Quoted 2 lines
That would be great!
thanks
Now on to the most important question: Will you merge this patch? :)
(It should probably go together with "tests/hmp: test "none" machine with memory".)

I posted a RFC to maintain this file with Marc-André Lureau, but not getting any acks yet, so I guess at least I don't have that permission, yet...

And I see Laruent posted this already:

[Qemu-devel] [PATCH v4 0/4] hmp: fix "dump-quest-memory" segfault

So I assume all these four patches can go with Dave's tree. Thanks,

Signature · 1 line

Peter Xu