<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools, branch v6.12.85</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>x86-64: rename misleadingly named '__copy_user_nocache()' function</title>
<updated>2026-04-22T11:19:01+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-03-30T17:39:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=14b9194db4a28421a4dbe5d6e519efbaa7c5f3cd'/>
<id>14b9194db4a28421a4dbe5d6e519efbaa7c5f3cd</id>
<content type='text'>
commit d187a86de793f84766ea40b9ade7ac60aabbb4fe upstream.

This function was a masterclass in bad naming, for various historical
reasons.

It claimed to be a non-cached user copy.  It is literally _neither_ of
those things.  It's a specialty memory copy routine that uses
non-temporal stores for the destination (but not the source), and that
does exception handling for both source and destination accesses.

Also note that while it works for unaligned targets, any unaligned parts
(whether at beginning or end) will not use non-temporal stores, since
only words and quadwords can be non-temporal on x86.

The exception handling means that it _can_ be used for user space
accesses, but not on its own - it needs all the normal "start user space
access" logic around it.

But typically the user space access would be the source, not the
non-temporal destination.  That was the original intention of this,
where the destination was some fragile persistent memory target that
needed non-temporal stores in order to catch machine check exceptions
synchronously and deal with them gracefully.

Thus that non-descriptive name: one use case was to copy from user space
into a non-cached kernel buffer.  However, the existing users are a mix
of that intended use-case, and a couple of random drivers that just did
this as a performance tweak.

Some of those random drivers then actively misused the user copying
version (with STAC/CLAC and all) to do kernel copies without ever even
caring about the exception handling, _just_ for the non-temporal
destination.

Rename it as a first small step to actually make it halfway sane, and
change the prototype to be more normal: it doesn't take a user pointer
unless the caller has done the proper conversion, and the argument size
is the full size_t (it still won't actually copy more than 4GB in one
go, but there's also no reason to silently truncate the size argument in
the caller).

Finally, use this now sanely named function in the NTB code, which
mis-used a user copy version (with STAC/CLAC and all) of this interface
despite it not actually being a user copy at all.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d187a86de793f84766ea40b9ade7ac60aabbb4fe upstream.

This function was a masterclass in bad naming, for various historical
reasons.

It claimed to be a non-cached user copy.  It is literally _neither_ of
those things.  It's a specialty memory copy routine that uses
non-temporal stores for the destination (but not the source), and that
does exception handling for both source and destination accesses.

Also note that while it works for unaligned targets, any unaligned parts
(whether at beginning or end) will not use non-temporal stores, since
only words and quadwords can be non-temporal on x86.

The exception handling means that it _can_ be used for user space
accesses, but not on its own - it needs all the normal "start user space
access" logic around it.

But typically the user space access would be the source, not the
non-temporal destination.  That was the original intention of this,
where the destination was some fragile persistent memory target that
needed non-temporal stores in order to catch machine check exceptions
synchronously and deal with them gracefully.

Thus that non-descriptive name: one use case was to copy from user space
into a non-cached kernel buffer.  However, the existing users are a mix
of that intended use-case, and a couple of random drivers that just did
this as a performance tweak.

Some of those random drivers then actively misused the user copying
version (with STAC/CLAC and all) to do kernel copies without ever even
caring about the exception handling, _just_ for the non-temporal
destination.

Rename it as a first small step to actually make it halfway sane, and
change the prototype to be more normal: it doesn't take a user pointer
unless the caller has done the proper conversion, and the argument size
is the full size_t (it still won't actually copy more than 4GB in one
go, but there's also no reason to silently truncate the size argument in
the caller).

Finally, use this now sanely named function in the NTB code, which
mis-used a user copy version (with STAC/CLAC and all) of this interface
despite it not actually being a user copy at all.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests: net: bridge_vlan_mcast: wait for h1 before querier check</title>
<updated>2026-04-22T11:18:53+00:00</updated>
<author>
<name>Daniel Golle</name>
<email>daniel@makrotopia.org</email>
</author>
<published>2026-04-05T21:29:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c2275ac1a9a3ded61785da479410a4521b0749a3'/>
<id>c2275ac1a9a3ded61785da479410a4521b0749a3</id>
<content type='text'>
[ Upstream commit efaa71faf212324ecbf6d5339e9717fe53254f58 ]

The querier-interval test adds h1 (currently a slave of the VRF created
by simple_if_init) to a temporary bridge br1 acting as an outside IGMP
querier. The kernel VRF driver (drivers/net/vrf.c) calls cycle_netdev()
on every slave add and remove, toggling the interface admin-down then up.
Phylink takes the PHY down during the admin-down half of that cycle.
Since h1 and swp1 are cable-connected, swp1 also loses its link may need
several seconds to re-negotiate.

Use setup_wait_dev $h1 0 which waits for h1 to return to UP state, so the
test can rely on the link being back up at this point.

Fixes: 4d8610ee8bd77 ("selftests: net: bridge: add vlan mcast_querier_interval tests")
Signed-off-by: Daniel Golle &lt;daniel@makrotopia.org&gt;
Reviewed-by: Alexander Sverdlin &lt;alexander.sverdlin@siemens.com&gt;
Link: https://patch.msgid.link/c830f130860fd2efae08bfb9e5b25fd028e58ce5.1775424423.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit efaa71faf212324ecbf6d5339e9717fe53254f58 ]

The querier-interval test adds h1 (currently a slave of the VRF created
by simple_if_init) to a temporary bridge br1 acting as an outside IGMP
querier. The kernel VRF driver (drivers/net/vrf.c) calls cycle_netdev()
on every slave add and remove, toggling the interface admin-down then up.
Phylink takes the PHY down during the admin-down half of that cycle.
Since h1 and swp1 are cable-connected, swp1 also loses its link may need
several seconds to re-negotiate.

Use setup_wait_dev $h1 0 which waits for h1 to return to UP state, so the
test can rely on the link being back up at this point.

Fixes: 4d8610ee8bd77 ("selftests: net: bridge: add vlan mcast_querier_interval tests")
Signed-off-by: Daniel Golle &lt;daniel@makrotopia.org&gt;
Reviewed-by: Alexander Sverdlin &lt;alexander.sverdlin@siemens.com&gt;
Link: https://patch.msgid.link/c830f130860fd2efae08bfb9e5b25fd028e58ce5.1775424423.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tools/power/turbostat: Fix microcode patch level output for AMD/Hygon</title>
<updated>2026-04-22T11:18:50+00:00</updated>
<author>
<name>Serhii Pievniev</name>
<email>spevnev16@gmail.com</email>
</author>
<published>2026-02-25T23:16:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=29af688c457a6f63484969fcd5ac040c78b1d286'/>
<id>29af688c457a6f63484969fcd5ac040c78b1d286</id>
<content type='text'>
[ Upstream commit a444083286434ec1fd127c5da11a3091e6013008 ]

turbostat always used the same logic to read the microcode patch level,
which is correct for Intel but not for AMD/Hygon.
While Intel stores the patch level in the upper 32 bits of MSR, AMD
stores it in the lower 32 bits, which causes turbostat to report the
microcode version as 0x0 on AMD/Hygon.

Fix by shifting right by 32 for non-AMD/Hygon, preserving the existing
behavior for Intel and unknown vendors.

Fixes: 3e4048466c39 ("tools/power turbostat: Add --no-msr option")
Signed-off-by: Serhii Pievniev &lt;spevnev16@gmail.com&gt;
Signed-off-by: Len Brown &lt;len.brown@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a444083286434ec1fd127c5da11a3091e6013008 ]

turbostat always used the same logic to read the microcode patch level,
which is correct for Intel but not for AMD/Hygon.
While Intel stores the patch level in the upper 32 bits of MSR, AMD
stores it in the lower 32 bits, which causes turbostat to report the
microcode version as 0x0 on AMD/Hygon.

Fix by shifting right by 32 for non-AMD/Hygon, preserving the existing
behavior for Intel and unknown vendors.

Fixes: 3e4048466c39 ("tools/power turbostat: Add --no-msr option")
Signed-off-by: Serhii Pievniev &lt;spevnev16@gmail.com&gt;
Signed-off-by: Len Brown &lt;len.brown@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests/bpf: test refining u32/s32 bounds when ranges cross min/max boundary</title>
<updated>2026-04-11T12:24:55+00:00</updated>
<author>
<name>Eduard Zingerman</name>
<email>eddyz87@gmail.com</email>
</author>
<published>2026-04-04T08:15:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=787781697f21688ba58a28252a81100fc7ce83ff'/>
<id>787781697f21688ba58a28252a81100fc7ce83ff</id>
<content type='text'>
[ Upstream commit f81fdfd16771e266753146bd83f6dd23515ebee9 ]

Two test cases for signed/unsigned 32-bit bounds refinement
when s32 range crosses the sign boundary:
- s32 range [S32_MIN..1] overlapping with u32 range [3..U32_MAX],
  s32 range tail before sign boundary overlaps with u32 range.
- s32 range [-3..5] overlapping with u32 range [0..S32_MIN+3],
  s32 range head after the sign boundary overlaps with u32 range.

This covers both branches added in the __reg32_deduce_bounds().

Also, crossing_32_bit_signed_boundary_2() no longer triggers invariant
violations.

Reviewed-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Reviewed-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Acked-by: Shung-Hsi Yu &lt;shung-hsi.yu@suse.com&gt;
Signed-off-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260306-bpf-32-bit-range-overflow-v3-2-f7f67e060a6b@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit f81fdfd16771e266753146bd83f6dd23515ebee9 ]

Two test cases for signed/unsigned 32-bit bounds refinement
when s32 range crosses the sign boundary:
- s32 range [S32_MIN..1] overlapping with u32 range [3..U32_MAX],
  s32 range tail before sign boundary overlaps with u32 range.
- s32 range [-3..5] overlapping with u32 range [0..S32_MIN+3],
  s32 range head after the sign boundary overlaps with u32 range.

This covers both branches added in the __reg32_deduce_bounds().

Also, crossing_32_bit_signed_boundary_2() no longer triggers invariant
violations.

Reviewed-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Reviewed-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Acked-by: Shung-Hsi Yu &lt;shung-hsi.yu@suse.com&gt;
Signed-off-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260306-bpf-32-bit-range-overflow-v3-2-f7f67e060a6b@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Fix u32/s32 bounds when ranges cross min/max boundary</title>
<updated>2026-04-11T12:24:55+00:00</updated>
<author>
<name>Eduard Zingerman</name>
<email>eddyz87@gmail.com</email>
</author>
<published>2026-04-04T08:14:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ded1ea20d0b77d511ed16bbf14766a9d354bde8b'/>
<id>ded1ea20d0b77d511ed16bbf14766a9d354bde8b</id>
<content type='text'>
[ Upstream commit fbc7aef517d8765e4c425d2792409bb9bf2e1f13 ]

Same as in __reg64_deduce_bounds(), refine s32/u32 ranges
in __reg32_deduce_bounds() in the following situations:

- s32 range crosses U32_MAX/0 boundary, positive part of the s32 range
  overlaps with u32 range:

  0                                                   U32_MAX
  |  [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx]              |
  |----------------------------|----------------------------|
  |xxxxx s32 range xxxxxxxxx]                       [xxxxxxx|
  0                     S32_MAX S32_MIN                    -1

- s32 range crosses U32_MAX/0 boundary, negative part of the s32 range
  overlaps with u32 range:

  0                                                   U32_MAX
  |              [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx]  |
  |----------------------------|----------------------------|
  |xxxxxxxxx]                       [xxxxxxxxxxxx s32 range |
  0                     S32_MAX S32_MIN                    -1

- No refinement if ranges overlap in two intervals.

This helps for e.g. consider the following program:

   call %[bpf_get_prandom_u32];
   w0 &amp;= 0xffffffff;
   if w0 &lt; 0x3 goto 1f;    // on fall-through u32 range [3..U32_MAX]
   if w0 s&gt; 0x1 goto 1f;   // on fall-through s32 range [S32_MIN..1]
   if w0 s&lt; 0x0 goto 1f;   // range can be narrowed to  [S32_MIN..-1]
   r10 = 0;
1: ...;

The reg_bounds.c selftest is updated to incorporate identical logic,
refinement based on non-overflowing range halves:

  ((x ∩ [0, smax]) ∩ (y ∩ [0, smax])) ∪
  ((x ∩ [smin,-1]) ∩ (y ∩ [smin,-1]))

Reported-by: Andrea Righi &lt;arighi@nvidia.com&gt;
Reported-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Closes: https://lore.kernel.org/bpf/aakqucg4vcujVwif@gpd4/T/
Reviewed-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Acked-by: Shung-Hsi Yu &lt;shung-hsi.yu@suse.com&gt;
Signed-off-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260306-bpf-32-bit-range-overflow-v3-1-f7f67e060a6b@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit fbc7aef517d8765e4c425d2792409bb9bf2e1f13 ]

Same as in __reg64_deduce_bounds(), refine s32/u32 ranges
in __reg32_deduce_bounds() in the following situations:

- s32 range crosses U32_MAX/0 boundary, positive part of the s32 range
  overlaps with u32 range:

  0                                                   U32_MAX
  |  [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx]              |
  |----------------------------|----------------------------|
  |xxxxx s32 range xxxxxxxxx]                       [xxxxxxx|
  0                     S32_MAX S32_MIN                    -1

- s32 range crosses U32_MAX/0 boundary, negative part of the s32 range
  overlaps with u32 range:

  0                                                   U32_MAX
  |              [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx]  |
  |----------------------------|----------------------------|
  |xxxxxxxxx]                       [xxxxxxxxxxxx s32 range |
  0                     S32_MAX S32_MIN                    -1

- No refinement if ranges overlap in two intervals.

This helps for e.g. consider the following program:

   call %[bpf_get_prandom_u32];
   w0 &amp;= 0xffffffff;
   if w0 &lt; 0x3 goto 1f;    // on fall-through u32 range [3..U32_MAX]
   if w0 s&gt; 0x1 goto 1f;   // on fall-through s32 range [S32_MIN..1]
   if w0 s&lt; 0x0 goto 1f;   // range can be narrowed to  [S32_MIN..-1]
   r10 = 0;
1: ...;

The reg_bounds.c selftest is updated to incorporate identical logic,
refinement based on non-overflowing range halves:

  ((x ∩ [0, smax]) ∩ (y ∩ [0, smax])) ∪
  ((x ∩ [smin,-1]) ∩ (y ∩ [smin,-1]))

Reported-by: Andrea Righi &lt;arighi@nvidia.com&gt;
Reported-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Closes: https://lore.kernel.org/bpf/aakqucg4vcujVwif@gpd4/T/
Reviewed-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Acked-by: Shung-Hsi Yu &lt;shung-hsi.yu@suse.com&gt;
Signed-off-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260306-bpf-32-bit-range-overflow-v3-1-f7f67e060a6b@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Add third round of bounds deduction</title>
<updated>2026-04-11T12:24:55+00:00</updated>
<author>
<name>Paul Chaignon</name>
<email>paul.chaignon@gmail.com</email>
</author>
<published>2026-04-04T08:13:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=58d4c4a257ad4a46a3220877f360d3e97777e07c'/>
<id>58d4c4a257ad4a46a3220877f360d3e97777e07c</id>
<content type='text'>
[ Upstream commit 5dbb19b16ac498b0b7f3a8a85f9d25d6d8af397d ]

Commit d7f008738171 ("bpf: try harder to deduce register bounds from
different numeric domains") added a second call to __reg_deduce_bounds
in reg_bounds_sync because a single call wasn't enough to converge to a
fixed point in terms of register bounds.

With patch "bpf: Improve bounds when s64 crosses sign boundary" from
this series, Eduard noticed that calling __reg_deduce_bounds twice isn't
enough anymore to converge. The first selftest added in "selftests/bpf:
Test cross-sign 64bits range refinement" highlights the need for a third
call to __reg_deduce_bounds. After instruction 7, reg_bounds_sync
performs the following bounds deduction:

  reg_bounds_sync entry:          scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146)
  __update_reg_bounds:            scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146)
  __reg_deduce_bounds:
      __reg32_deduce_bounds:      scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146,umin32=0xfffffcf1,umax32=0xffffff6e)
      __reg64_deduce_bounds:      scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146,umin32=0xfffffcf1,umax32=0xffffff6e)
      __reg_deduce_mixed_bounds:  scalar(smin=-655,smax=0xeffffeee,umin=umin32=0xfffffcf1,umax=0xffffffffffffff6e,smin32=-783,smax32=-146,umax32=0xffffff6e)
  __reg_deduce_bounds:
      __reg32_deduce_bounds:      scalar(smin=-655,smax=0xeffffeee,umin=umin32=0xfffffcf1,umax=0xffffffffffffff6e,smin32=-783,smax32=-146,umax32=0xffffff6e)
      __reg64_deduce_bounds:      scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e)
      __reg_deduce_mixed_bounds:  scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e)
  __reg_bound_offset:             scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e,var_off=(0xfffffffffffffc00; 0x3ff))
  __update_reg_bounds:            scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e,var_off=(0xfffffffffffffc00; 0x3ff))

In particular, notice how:
1. In the first call to __reg_deduce_bounds, __reg32_deduce_bounds
   learns new u32 bounds.
2. __reg64_deduce_bounds is unable to improve bounds at this point.
3. __reg_deduce_mixed_bounds derives new u64 bounds from the u32 bounds.
4. In the second call to __reg_deduce_bounds, __reg64_deduce_bounds
   improves the smax and umin bounds thanks to patch "bpf: Improve
   bounds when s64 crosses sign boundary" from this series.
5. Subsequent functions are unable to improve the ranges further (only
   tnums). Yet, a better smin32 bound could be learned from the smin
   bound.

__reg32_deduce_bounds is able to improve smin32 from smin, but for that
we need a third call to __reg_deduce_bounds.

As discussed in [1], there may be a better way to organize the deduction
rules to learn the same information with less calls to the same
functions. Such an optimization requires further analysis and is
orthogonal to the present patchset.

Link: https://lore.kernel.org/bpf/aIKtSK9LjQXB8FLY@mail.gmail.com/ [1]
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Co-developed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Link: https://lore.kernel.org/r/79619d3b42e5525e0e174ed534b75879a5ba15de.1753695655.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 5dbb19b16ac498b0b7f3a8a85f9d25d6d8af397d ]

Commit d7f008738171 ("bpf: try harder to deduce register bounds from
different numeric domains") added a second call to __reg_deduce_bounds
in reg_bounds_sync because a single call wasn't enough to converge to a
fixed point in terms of register bounds.

With patch "bpf: Improve bounds when s64 crosses sign boundary" from
this series, Eduard noticed that calling __reg_deduce_bounds twice isn't
enough anymore to converge. The first selftest added in "selftests/bpf:
Test cross-sign 64bits range refinement" highlights the need for a third
call to __reg_deduce_bounds. After instruction 7, reg_bounds_sync
performs the following bounds deduction:

  reg_bounds_sync entry:          scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146)
  __update_reg_bounds:            scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146)
  __reg_deduce_bounds:
      __reg32_deduce_bounds:      scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146,umin32=0xfffffcf1,umax32=0xffffff6e)
      __reg64_deduce_bounds:      scalar(smin=-655,smax=0xeffffeee,smin32=-783,smax32=-146,umin32=0xfffffcf1,umax32=0xffffff6e)
      __reg_deduce_mixed_bounds:  scalar(smin=-655,smax=0xeffffeee,umin=umin32=0xfffffcf1,umax=0xffffffffffffff6e,smin32=-783,smax32=-146,umax32=0xffffff6e)
  __reg_deduce_bounds:
      __reg32_deduce_bounds:      scalar(smin=-655,smax=0xeffffeee,umin=umin32=0xfffffcf1,umax=0xffffffffffffff6e,smin32=-783,smax32=-146,umax32=0xffffff6e)
      __reg64_deduce_bounds:      scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e)
      __reg_deduce_mixed_bounds:  scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e)
  __reg_bound_offset:             scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e,var_off=(0xfffffffffffffc00; 0x3ff))
  __update_reg_bounds:            scalar(smin=-655,smax=smax32=-146,umin=0xfffffffffffffd71,umax=0xffffffffffffff6e,smin32=-783,umin32=0xfffffcf1,umax32=0xffffff6e,var_off=(0xfffffffffffffc00; 0x3ff))

In particular, notice how:
1. In the first call to __reg_deduce_bounds, __reg32_deduce_bounds
   learns new u32 bounds.
2. __reg64_deduce_bounds is unable to improve bounds at this point.
3. __reg_deduce_mixed_bounds derives new u64 bounds from the u32 bounds.
4. In the second call to __reg_deduce_bounds, __reg64_deduce_bounds
   improves the smax and umin bounds thanks to patch "bpf: Improve
   bounds when s64 crosses sign boundary" from this series.
5. Subsequent functions are unable to improve the ranges further (only
   tnums). Yet, a better smin32 bound could be learned from the smin
   bound.

__reg32_deduce_bounds is able to improve smin32 from smin, but for that
we need a third call to __reg_deduce_bounds.

As discussed in [1], there may be a better way to organize the deduction
rules to learn the same information with less calls to the same
functions. Such an optimization requires further analysis and is
orthogonal to the present patchset.

Link: https://lore.kernel.org/bpf/aIKtSK9LjQXB8FLY@mail.gmail.com/ [1]
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Co-developed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Link: https://lore.kernel.org/r/79619d3b42e5525e0e174ed534b75879a5ba15de.1753695655.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests/bpf: Test invariants on JSLT crossing sign</title>
<updated>2026-04-11T12:24:55+00:00</updated>
<author>
<name>Paul Chaignon</name>
<email>paul.chaignon@gmail.com</email>
</author>
<published>2026-04-04T08:12:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d7a73ec8015bcfdf8629f191dbbf07a089fbb741'/>
<id>d7a73ec8015bcfdf8629f191dbbf07a089fbb741</id>
<content type='text'>
[ Upstream commit f96841bbf4a1ee4ed0336ba192a01278fdea6383 ]

The improvement of the u64/s64 range refinement fixed the invariant
violation that was happening on this test for BPF_JSLT when crossing the
sign boundary.

After this patch, we have one test remaining with a known invariant
violation. It's the same test as fixed here but for 32 bits ranges.

Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Link: https://lore.kernel.org/r/ad046fb0016428f1a33c3b81617aabf31b51183f.1753695655.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit f96841bbf4a1ee4ed0336ba192a01278fdea6383 ]

The improvement of the u64/s64 range refinement fixed the invariant
violation that was happening on this test for BPF_JSLT when crossing the
sign boundary.

After this patch, we have one test remaining with a known invariant
violation. It's the same test as fixed here but for 32 bits ranges.

Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Link: https://lore.kernel.org/r/ad046fb0016428f1a33c3b81617aabf31b51183f.1753695655.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests/bpf: Test cross-sign 64bits range refinement</title>
<updated>2026-04-11T12:24:55+00:00</updated>
<author>
<name>Paul Chaignon</name>
<email>paul.chaignon@gmail.com</email>
</author>
<published>2026-04-04T08:11:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=269d80981a5c79246fd5594b3603cdda0d0205bb'/>
<id>269d80981a5c79246fd5594b3603cdda0d0205bb</id>
<content type='text'>
[ Upstream commit 26e5e346a52c796190e63af1c2a80a417fda261a ]

This patch adds coverage for the new cross-sign 64bits range refinement
logic. The three tests cover the cases when the u64 and s64 ranges
overlap (1) in the negative portion of s64, (2) in the positive portion
of s64, and (3) in both portions.

The first test is a simplified version of a BPF program generated by
syzkaller that caused an invariant violation [1]. It looks like
syzkaller could not extract the reproducer itself (and therefore didn't
report it to the mailing list), but I was able to extract it from the
console logs of a crash.

The principle is similar to the invariant violation described in
commit 6279846b9b25 ("bpf: Forget ranges when refining tnum after
JSET"): the verifier walks a dead branch, uses the condition to refine
ranges, and ends up with inconsistent ranges. In this case, the dead
branch is when we fallthrough on both jumps. The new refinement logic
improves the bounds such that the second jump is properly detected as
always-taken and the verifier doesn't end up walking a dead branch.

The second and third tests are inspired by the first, but rely on
condition jumps to prepare the bounds instead of ALU instructions. An
R10 write is used to trigger a verifier error when the bounds can't be
refined.

Link: https://syzkaller.appspot.com/bug?extid=c711ce17dd78e5d4fdcf [1]
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Link: https://lore.kernel.org/r/a0e17b00dab8dabcfa6f8384e7e151186efedfdd.1753695655.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 26e5e346a52c796190e63af1c2a80a417fda261a ]

This patch adds coverage for the new cross-sign 64bits range refinement
logic. The three tests cover the cases when the u64 and s64 ranges
overlap (1) in the negative portion of s64, (2) in the positive portion
of s64, and (3) in both portions.

The first test is a simplified version of a BPF program generated by
syzkaller that caused an invariant violation [1]. It looks like
syzkaller could not extract the reproducer itself (and therefore didn't
report it to the mailing list), but I was able to extract it from the
console logs of a crash.

The principle is similar to the invariant violation described in
commit 6279846b9b25 ("bpf: Forget ranges when refining tnum after
JSET"): the verifier walks a dead branch, uses the condition to refine
ranges, and ends up with inconsistent ranges. In this case, the dead
branch is when we fallthrough on both jumps. The new refinement logic
improves the bounds such that the second jump is properly detected as
always-taken and the verifier doesn't end up walking a dead branch.

The second and third tests are inspired by the first, but rely on
condition jumps to prepare the bounds instead of ALU instructions. An
R10 write is used to trigger a verifier error when the bounds can't be
refined.

Link: https://syzkaller.appspot.com/bug?extid=c711ce17dd78e5d4fdcf [1]
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Link: https://lore.kernel.org/r/a0e17b00dab8dabcfa6f8384e7e151186efedfdd.1753695655.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>objtool: Fix Clang jump table detection</title>
<updated>2026-04-11T12:24:29+00:00</updated>
<author>
<name>Josh Poimboeuf</name>
<email>jpoimboe@kernel.org</email>
</author>
<published>2026-03-09T16:03:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e3da29787887c433b78155f0f52c268b7f273e7b'/>
<id>e3da29787887c433b78155f0f52c268b7f273e7b</id>
<content type='text'>
[ Upstream commit 4e5019216402ad0b4a84cff457b662d26803f103 ]

With Clang, there can be a conditional forward jump between the load of
the jump table address and the indirect branch.

Fixes the following warning:

  vmlinux.o: warning: objtool: ___bpf_prog_run+0x1c5: sibling call from callable instruction with modified stack frame

Reported-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com
Link: https://patch.msgid.link/7d8600caed08901b6679767488acd639f6df9688.1773071992.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 4e5019216402ad0b4a84cff457b662d26803f103 ]

With Clang, there can be a conditional forward jump between the load of
the jump table address and the indirect branch.

Fixes the following warning:

  vmlinux.o: warning: objtool: ___bpf_prog_run+0x1c5: sibling call from callable instruction with modified stack frame

Reported-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com
Link: https://patch.msgid.link/7d8600caed08901b6679767488acd639f6df9688.1773071992.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>objtool: Handle Clang RSP musical chairs</title>
<updated>2026-04-02T11:09:29+00:00</updated>
<author>
<name>Josh Poimboeuf</name>
<email>jpoimboe@kernel.org</email>
</author>
<published>2026-03-06T17:35:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fee55fffbfcd93079fd496737ac7f6db1ddcfe4a'/>
<id>fee55fffbfcd93079fd496737ac7f6db1ddcfe4a</id>
<content type='text'>
[ Upstream commit 7fdaa640c810cb42090a182c33f905bcc47a616a ]

For no apparent reason (possibly related to CONFIG_KMSAN), Clang can
randomly pass the value of RSP to other registers and then back again to
RSP.  Handle that accordingly.

Fixes the following warnings:

  drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state
  drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1

Reported-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com
Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 7fdaa640c810cb42090a182c33f905bcc47a616a ]

For no apparent reason (possibly related to CONFIG_KMSAN), Clang can
randomly pass the value of RSP to other registers and then back again to
RSP.  Handle that accordingly.

Fixes the following warnings:

  drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state
  drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1

Reported-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com
Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
