February 2025 - Linux-kselftest-mirror

[PATCH net-next v4 0/8] netconsole: Add support for CPU population

by Breno Leitao

The current implementation of netconsole sends all log messages in parallel, which can lead to an intermixed and interleaved output on the receiving side. This makes it challenging to demultiplex the messages and attribute them to their originating CPUs. As a result, users and developers often struggle to effectively analyze and debug the parallel log output received through netconsole. Example of a message got from produciton hosts: ------------[ cut here ]------------ ------------[ cut here ]------------ refcount_t: saturated; leaking memory. WARNING: CPU: 2 PID: 1613668 at lib/refcount.c:22 refcount_warn_saturate+0x5e/0xe0 refcount_t: addition on 0; use-after-free. WARNING: CPU: 26 PID: 4139916 at lib/refcount.c:25 refcount_warn_saturate+0x7d/0xe0 Modules linked in: bpf_preload(E) vhost_net(E) tun(E) vhost(E) This series of patches introduces a new feature to the netconsole subsystem that allows the automatic population of the CPU number in the userdata field for each log message. This enhancement provides several benefits: * Improved demultiplexing of parallel log output: When multiple CPUs are sending messages concurrently, the added CPU number in the userdata makes it easier to differentiate and attribute the messages to their originating CPUs. * Better visibility into message sources: The CPU number information gives users and developers more insight into which specific CPU a particular log message came from, which can be valuable for debugging and analysis. The changes in this series are as follows Patches:: Patch "consolidate send buffers into netconsole_target struct" ================================================= Move the static buffers to netconsole target, from static declaration in send_msg_no_fragmentation() and send_msg_fragmented(). Patch "netconsole: Rename userdata to extradata" ================================================= Create the a concept of extradata, which encompasses the concept of userdata and the upcoming sysdatao Sysdata is a new concept being added, which is basically fields that are populated by the kernel. At this time only the CPU#, but, there is a desire to add current task name, kernel release version, etc. Patch "netconsole: Helper to count number of used entries" =========================================================== Create a simple helper to count number of entries in extradata. I am separating this in a function since it will need to count userdata and sysdata. For instance, when the user adds an extra userdata, we need to check if there is space, counting the previous data entries (from userdata and cpu data) Patch "Introduce configfs helpers for sysdata features" ====================================================== Create the concept of sysdata feature in the netconsole target, and create the configfs helpers to enable the bit in nt->sysdata Patch "Include sysdata in extradata entry count" ================================================ Add the concept of sysdata when counting for available space in the buffer. This will protect users from creating new userdata/sysdata if there is no more space Patch "netconsole: add support for sysdata and CPU population" =============================================================== This is the core patch. Basically add a new option to enable automatic CPU number population in the netconsole userdata Provides a new "cpu_nr" sysfs attribute to control this feature Patch "netconsole: selftest: test CPU number auto-population" ============================================================= Expands the existing netconsole selftest to verify the CPU number auto-population functionality Ensures the received netconsole messages contain the expected "cpu=<CPU>" entry in the message. Test different permutation with userdata Patch "netconsole: docs: Add documentation for CPU number auto-population" ============================================================================= Updates the netconsole documentation to explain the new CPU number auto-population feature Provides instructions on how to enable and use the feature I believe these changes will be a valuable addition to the netconsole subsystem, enhancing its usefulness for kernel developers and users. PS: This patchset is on top of the patch that created netcons_fragmented_msg selftest: https://lore.kernel.org/all/20250203-netcons_frag_msgs-v1-1-5bc6bedf2ac0@de… Signed-off-by: Breno Leitao <leitao(a)debian.org> --- Changes in v4: - Fixed Kernel doc for netconsole_target (Simon) - Fixed a typo in disable_sysdata_feature (Simon) - Improved sysdata_cpu_nr_show() to return !! in a bit-wise operation - Link to v3: https://lore.kernel.org/r/20250124-netcon_cpu-v3-0-12a0d286ba1d@debian.org Changes in v3: - Moved the buffer into netconsole_target, avoiding static functions in the send path (Jakub). - Fix a documentation error (Randy Dunlap) - Created a function that handle all the extradata, consolidating it in a single place (Jakub) - Split the patch even more, trying to simplify the review. - Link to v2: https://lore.kernel.org/r/20250115-netcon_cpu-v2-0-95971b44dc56@debian.org Changes in v2: - Create the concept of extradata and sysdata. This will make the design easier to understand, and the code easier to read. * Basically extradata encompasses userdata and the new sysdata. Userdata originates from user, and sysdata originates in kernel. - Improved the test to send from a very specific CPU, which can be checked to be correct on the other side, as suggested by Jakub. - Fixed a bug where CPU # was populated at the wrong place - Link to v1: https://lore.kernel.org/r/20241113-netcon_cpu-v1-0-d187bf7c0321@debian.org --- Breno Leitao (8): netconsole: consolidate send buffers into netconsole_target struct netconsole: Rename userdata to extradata netconsole: Helper to count number of used entries netconsole: Introduce configfs helpers for sysdata features netconsole: Include sysdata in extradata entry count netconsole: add support for sysdata and CPU population netconsole: selftest: test for sysdata CPU netconsole: docs: Add documentation for CPU number auto-population Documentation/networking/netconsole.rst | 45 ++++ drivers/net/netconsole.c | 261 ++++++++++++++++----- tools/testing/selftests/drivers/net/Makefile | 1 + .../selftests/drivers/net/lib/sh/lib_netcons.sh | 17 ++ .../selftests/drivers/net/netcons_sysdata.sh | 167 +++++++++++++ 5 files changed, 427 insertions(+), 64 deletions(-) --- base-commit: 145702ca2544bf82c6b244a49163f603fbe746f4 change-id: 20241108-netcon_cpu-ce3917e88f4b Best regards, -- Breno Leitao <leitao(a)debian.org>

8 months, 3 weeks

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[PATCH v2 0/2] tools/nolibc: support for 32-bit s390

by Thomas Weißschuh

Support for 32-bit s390 is very easy to implement and useful for testing. For example I used to test some generic compat_ptr() logic, which is only testable on 32-bit s390. The series depends on my other series "selftests/nolibc: test kernel configuration cleanups". (It's not a hard dependency, only a minor diff conflict) Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> --- Changes in v2: - Rebase unto nolibc-next - Use 96 bytes of stack frame size - Pick up Ack from Willy - Link to v1: https://lore.kernel.org/r/20250122-nolibc-s390-v1-0-8c765f00e871@weissschuh… --- Thomas Weißschuh (2): selftests/nolibc: rename s390 to s390x tools/nolibc: add support for 32-bit s390 tools/include/nolibc/arch-s390.h | 5 +++++ tools/include/nolibc/arch.h | 2 +- tools/testing/selftests/nolibc/Makefile | 10 ++++++++-- tools/testing/selftests/nolibc/run-tests.sh | 7 ++++++- 4 files changed, 20 insertions(+), 4 deletions(-) --- base-commit: c1f4a7a84037249d086a4114c0c4332a260e9091 change-id: 20250122-nolibc-s390-e57141682c88 Best regards, -- Thomas Weißschuh <linux(a)weissschuh.net>

8 months, 3 weeks

1
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[PATCH bpf-next v8 0/5] xsk: TX metadata Launch Time support

by Song Yoong Siang

This series expands the XDP TX metadata framework to allow user applications to pass per packet 64-bit launch time directly to the kernel driver, requesting launch time hardware offload support. The XDP TX metadata framework will not perform any clock conversion or packet reordering. Please note that the role of Tx metadata is just to pass the launch time, not to enable the offload feature. Users will need to enable the launch time hardware offload feature of the device by using the respective command, such as the tc-etf command. Although some devices use the tc-etf command to enable their launch time hardware offload feature, xsk packets will not go through the etf qdisc. Therefore, in my opinion, the launch time should always be based on the PTP Hardware Clock (PHC). Thus, i did not include a clock ID to indicate the clock source. To simplify the test steps, I modified the xdp_hw_metadata bpf self-test tool in such a way that it will set the launch time based on the offset provided by the user and the value of the Receive Hardware Timestamp, which is against the PHC. This will eliminate the need to discipline System Clock with the PHC and then use clock_gettime() to get the time. Please note that AF_XDP lacks a feedback mechanism to inform the application if the requested launch time is invalid. So, users are expected to familiar with the horizon of the launch time of the device they use and not request a launch time that is beyond the horizon. Otherwise, the driver might interpret the launch time incorrectly and react wrongly. For stmmac and igc, where modulo computation is used, a launch time larger than the horizon will cause the device to transmit the packet earlier that the requested launch time. Although there is no feedback mechanism for the launch time request for now, user still can check whether the requested launch time is working or not, by requesting the Transmit Completion Hardware Timestamp. V8: - check the number of used descriptor in xsk_tx_metadata_request() by using used_desc of struct igc_metadata_request, and then decreases the budget with it (Maciej) V7: https://lore.kernel.org/netdev/20250204004907.789330-1-yoong.siang.song@int… - split the refactoring code of igc empty packet insertion into a separate commit (Faizal) - add explanation on why the value "4" is used as igc transmit budget (Faizal) - perform a stress test by sending 1000 packets with 10ms interval and launch time set to 500us in the future (Faizal & Yong Liang) V6: https://lore.kernel.org/netdev/20250116155350.555374-1-yoong.siang.song@int… - fix selftest build errors by using asprintf() and realloc(), instead of managing the buffer sizes manually (Daniel, Stanislav) V5: https://lore.kernel.org/netdev/20250114152718.120588-1-yoong.siang.song@int… - change netdev feature name from tx-launch-time to tx-launch-time-fifo to explicitly state the FIFO behaviour (Stanislav) - improve the looping of xdp_hw_metadata app to wait for packet tx completion to be more readable by using clock_gettime() (Stanislav) - add launch time setup steps into xdp_hw_metadata app (Stanislav) V4: https://lore.kernel.org/netdev/20250106135506.9687-1-yoong.siang.song@intel… - added XDP launch time support to the igc driver (Jesper & Florian) - added per-driver launch time limitation on xsk-tx-metadata.rst (Jesper) - added explanation on FIFO behavior on xsk-tx-metadata.rst (Jakub) - added step to enable launch time in the commit message (Jesper & Willem) - explicitly documented the type of launch_time and which clock source it is against (Willem) V3: https://lore.kernel.org/netdev/20231203165129.1740512-1-yoong.siang.song@in… - renamed to use launch time (Jesper & Willem) - changed the default launch time in xdp_hw_metadata apps from 1s to 0.1s because some NICs do not support such a large future time. V2: https://lore.kernel.org/netdev/20231201062421.1074768-1-yoong.siang.song@in… - renamed to use Earliest TxTime First (Willem) - renamed to use txtime (Willem) V1: https://lore.kernel.org/netdev/20231130162028.852006-1-yoong.siang.song@int… Song Yoong Siang (5): xsk: Add launch time hardware offload support to XDP Tx metadata selftests/bpf: Add launch time request to xdp_hw_metadata net: stmmac: Add launch time support to XDP ZC igc: Refactor empty packet insertion into a reusable function igc: Add launch time support to XDP ZC Documentation/netlink/specs/netdev.yaml | 4 + Documentation/networking/xsk-tx-metadata.rst | 62 +++++++ drivers/net/ethernet/intel/igc/igc.h | 1 + drivers/net/ethernet/intel/igc/igc_main.c | 94 +++++++--- drivers/net/ethernet/stmicro/stmmac/stmmac.h | 2 + .../net/ethernet/stmicro/stmmac/stmmac_main.c | 13 ++ include/net/xdp_sock.h | 10 ++ include/net/xdp_sock_drv.h | 1 + include/uapi/linux/if_xdp.h | 10 ++ include/uapi/linux/netdev.h | 3 + net/core/netdev-genl.c | 2 + net/xdp/xsk.c | 3 + tools/include/uapi/linux/if_xdp.h | 10 ++ tools/include/uapi/linux/netdev.h | 3 + tools/testing/selftests/bpf/xdp_hw_metadata.c | 168 +++++++++++++++++- 15 files changed, 359 insertions(+), 27 deletions(-) -- 2.34.1

8 months, 3 weeks

3
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[PATCH net-next] selftests: net: suppress ReST file generation when building selftests

by Jakub Kicinski

Some selftests need libynl.a. When building it try to skip generating the ReST documentation, libynl.a does not depend on them. Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> --- CC: donald.hunter(a)gmail.com CC: shuah(a)kernel.org CC: linux-kselftest(a)vger.kernel.org --- tools/testing/selftests/net/ynl.mk | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/ynl.mk b/tools/testing/selftests/net/ynl.mk index 12e7cae251be..e907c2751956 100644 --- a/tools/testing/selftests/net/ynl.mk +++ b/tools/testing/selftests/net/ynl.mk @@ -27,7 +27,8 @@ YNL_GENS_HASH := $(shell echo $(YNL_GENS) | sha1sum | cut -c1-8) $(OUTPUT)/libynl.a: $(YNL_SPECS) $(OUTPUT)/.libynl-$(YNL_GENS_HASH).sig $(Q)rm -f $(top_srcdir)/tools/net/ynl/libynl.a - $(Q)$(MAKE) -C $(top_srcdir)/tools/net/ynl GENS="$(YNL_GENS)" libynl.a + $(Q)$(MAKE) -C $(top_srcdir)/tools/net/ynl \ + GENS="$(YNL_GENS)" RSTS="" libynl.a $(Q)cp $(top_srcdir)/tools/net/ynl/libynl.a $(OUTPUT)/libynl.a EXTRA_CLEAN += \ -- 2.48.1

8 months, 3 weeks

3
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[PATCH net] selftests: mptcp: connect: -f: no reconnect

by Matthieu Baerts (NGI0)

The '-f' parameter is there to force the kernel to emit MPTCP FASTCLOSE by closing the connection with unread bytes in the receive queue. The xdisconnect() helper was used to stop the connection, but it does more than that: it will shut it down, then wait before reconnecting to the same address. This causes the mptcp_join's "fastclose test" to fail all the time. This failure is due to a recent change, with commit 218cc166321f ("selftests: mptcp: avoid spurious errors on disconnect"), but that went unnoticed because the test is currently ignored. The recent modification only shown an existing issue: xdisconnect() doesn't need to be used here, only the shutdown() part is needed. Fixes: 6bf41020b72b ("selftests: mptcp: update and extend fastclose test-cases") Cc: stable(a)vger.kernel.org Reviewed-by: Mat Martineau <martineau(a)kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- Notes: - The failure was not clearly visible on NIPA, because the results for the two impacted sub-tests are currently ignored (unstable). Still, it looks important to fix that, as this will help when the tests will be improved not to be unstable any more. --- tools/testing/selftests/net/mptcp/mptcp_connect.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c index 414addef9a4514c489ecd09249143fe0ce2af649..d240d02fa443a1cd802f0e705ab36db5c22063a8 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_connect.c +++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c @@ -1302,7 +1302,7 @@ int main_loop(void) return ret; if (cfg_truncate > 0) { - xdisconnect(fd); + shutdown(fd, SHUT_WR); } else if (--cfg_repeat > 0) { xdisconnect(fd); --- base-commit: 4241a702e0d0c2ca9364cfac08dbf134264962de change-id: 20250204-net-mptcp-sft-conn-f-d1c14274ba66 Best regards, -- Matthieu Baerts (NGI0) <matttbe(a)kernel.org>

8 months, 3 weeks

2
1
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[PATCH] selftests/dma: Fix bad array reference.

by Liu Ye

dir[directions] should be directions[dir] to correctly index the directions array. Signed-off-by: Liu Ye <liuye(a)kylinos.cn> --- tools/testing/selftests/dma/dma_map_benchmark.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/dma/dma_map_benchmark.c b/tools/testing/selftests/dma/dma_map_benchmark.c index b12f1f9babf8..b925756373ce 100644 --- a/tools/testing/selftests/dma/dma_map_benchmark.c +++ b/tools/testing/selftests/dma/dma_map_benchmark.c @@ -118,7 +118,7 @@ int main(int argc, char **argv) } printf("dma mapping benchmark: threads:%d seconds:%d node:%d dir:%s granule: %d\n", - threads, seconds, node, dir[directions], granule); + threads, seconds, node, directions[dir], granule); printf("average map latency(us):%.1f standard deviation:%.1f\n", map.avg_map_100ns/10.0, map.map_stddev/10.0); printf("average unmap latency(us):%.1f standard deviation:%.1f\n", -- 2.25.1

8 months, 3 weeks

1
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[PATCH] selftests: bpf: Support dynamic linking LLVM if static not available

by Daniel Xu

Since 67ab80a01886 ("selftests/bpf: Prefer static linking for LLVM libraries"), only statically linking test_progs is supported. However, some distros only provide a dynamically linkable LLVM. This commit adds a fallback for dynamically linking LLVM if static linking is not available. If both options are available, static linking is chosen. Signed-off-by: Daniel Xu <dxu(a)dxuuu.xyz> --- tools/testing/selftests/bpf/Makefile | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 6722080b2107..da514030a153 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -184,9 +184,14 @@ ifeq ($(feature-llvm),1) LLVM_CONFIG_LIB_COMPONENTS := mcdisassembler all-targets # both llvm-config and lib.mk add -D_GNU_SOURCE, which ends up as conflict LLVM_CFLAGS += $(filter-out -D_GNU_SOURCE,$(shell $(LLVM_CONFIG) --cflags)) - LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS)) - LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS)) - LLVM_LDLIBS += -lstdc++ + # Prefer linking statically if it's available, otherwise fallback to shared + ifeq ($(shell $(LLVM_CONFIG) --link-static --libs &> /dev/null && echo static),static) + LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS)) + LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS)) + LLVM_LDLIBS += -lstdc++ + else + LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-shared --libs $(LLVM_CONFIG_LIB_COMPONENTS)) + endif LLVM_LDFLAGS += $(shell $(LLVM_CONFIG) --ldflags) endif -- 2.47.1

8 months, 3 weeks

5
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[PATCH] selftests: pidfd: Fix compiling errors and warning

by I Hsin Cheng

When compiling selftests files under tools/testing/selftests/pidfd/ , some compiling errors and warnings will pop out as the following. CC pidfd_fdinfo_test pidfd_fdinfo_test.c: In function ‘child_fdinfo_nspid_test’: pidfd_fdinfo_test.c:231:13: warning: implicit declaration of function \ ‘mount’ [-Wimplicit-function-declaration] 231 | r = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0); | ^~~~~ pidfd_fdinfo_test.c:231:36: error: ‘MS_REC’ undeclared \ (first use in this function) 231 | r = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0); | ^~~~~~ pidfd_fdinfo_test.c:231:36: note: each undeclared identifier is \ reported only once for each function it appears in pidfd_fdinfo_test.c:231:45: error: ‘MS_PRIVATE’ undeclared \ (first use in this function); did you mean ‘MAP_PRIVATE’? 231 | r = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0); | ^~~~~~~~~~ | MAP_PRIVATE pidfd_fdinfo_test.c:237:15: warning: implicit declaration of function \ ‘umount2’; did you mean ‘SYS_umount2’? \ [-Wimplicit-function-declaration] 237 | (void)umount2("/proc", MNT_DETACH); | ^~~~~~~ | SYS_umount2 pidfd_fdinfo_test.c:237:32: error: ‘MNT_DETACH’ undeclared \ (first use in this function) 237 | (void)umount2("/proc", MNT_DETACH); | ^~~~~~~~~~ make: *** [../lib.mk:222: \ ~/linux/tools/testing/selftests/pidfd/pidfd_fdinfo_test] Error 1 Solve these errors and warnings by including header file <sys/mount.h>. Signed-off-by: I Hsin Cheng <richard120310(a)gmail.com> --- tools/testing/selftests/pidfd/pidfd_fdinfo_test.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c index f062a986e..f718aac75 100644 --- a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c +++ b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c @@ -13,6 +13,7 @@ #include <syscall.h> #include <sys/wait.h> #include <sys/mman.h> +#include <sys/mount.h> #include "pidfd.h" #include "../kselftest.h" -- 2.43.0

8 months, 3 weeks

2
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[PATCH 6.13 580/623] selftests/rseq: Fix handling of glibc without rseq support

by Greg Kroah-Hartman

6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> commit 336d02bc4c6bec5c3d933e5d470a94970f830957 upstream. When porting librseq commit: commit c7b45750fa85 ("Adapt to glibc __rseq_size feature detection") from librseq to the kernel selftests, the following line was missed at the end of rseq_init(): rseq_size = get_rseq_kernel_feature_size(); which effectively leaves rseq_size initialized to -1U when glibc does not have rseq support. glibc supports rseq from version 2.35 onwards. In a following librseq commit commit c67d198627c2 ("Only set 'rseq_size' on first thread registration") to mimic the libc behavior, a new approach is taken: don't set the feature size in 'rseq_size' until at least one thread has successfully registered. This allows using 'rseq_size' in fast-paths to test for both registration status and available features. The caveat is that on libc either all threads are registered or none are, while with bare librseq it is the responsability of the user to register all threads using rseq. This combines the changes from the following librseq git commits: commit c7b45750fa85 ("Adapt to glibc __rseq_size feature detection") commit c67d198627c2 ("Only set 'rseq_size' on first thread registration") Fixes: a0cc649353bb ("selftests/rseq: Fix mm_cid test failure") Reported-by: Raghavendra Rao Ananta <rananta(a)google.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: Raghavendra Rao Ananta <rananta(a)google.com> Cc: Shuah Khan <skhan(a)linuxfoundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Boqun Feng <boqun.feng(a)gmail.com> Cc: "Paul E. McKenney" <paulmck(a)kernel.org> Cc: Carlos O'Donell <carlos(a)redhat.com> Cc: Florian Weimer <fweimer(a)redhat.com> Cc: Michael Jeanson <mjeanson(a)efficios.com> Cc: linux-kselftest(a)vger.kernel.org Cc: stable(a)vger.kernel.org Signed-off-by: Shuah Khan <skhan(a)linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- tools/testing/selftests/rseq/rseq.c | 32 +++++++++++++++++++++++++------- tools/testing/selftests/rseq/rseq.h | 9 ++++++++- 2 files changed, 33 insertions(+), 8 deletions(-) --- a/tools/testing/selftests/rseq/rseq.c +++ b/tools/testing/selftests/rseq/rseq.c @@ -61,7 +61,6 @@ unsigned int rseq_size = -1U; unsigned int rseq_flags; static int rseq_ownership; -static int rseq_reg_success; /* At least one rseq registration has succeded. */ /* Allocate a large area for the TLS. */ #define RSEQ_THREAD_AREA_ALLOC_SIZE 1024 @@ -152,14 +151,27 @@ int rseq_register_current_thread(void) } rc = sys_rseq(&__rseq_abi, get_rseq_min_alloc_size(), 0, RSEQ_SIG); if (rc) { - if (RSEQ_READ_ONCE(rseq_reg_success)) { + /* + * After at least one thread has registered successfully + * (rseq_size > 0), the registration of other threads should + * never fail. + */ + if (RSEQ_READ_ONCE(rseq_size) > 0) { /* Incoherent success/failure within process. */ abort(); } return -1; } assert(rseq_current_cpu_raw() >= 0); - RSEQ_WRITE_ONCE(rseq_reg_success, 1); + + /* + * The first thread to register sets the rseq_size to mimic the libc + * behavior. + */ + if (RSEQ_READ_ONCE(rseq_size) == 0) { + RSEQ_WRITE_ONCE(rseq_size, get_rseq_kernel_feature_size()); + } + return 0; } @@ -235,12 +247,18 @@ void rseq_init(void) return; } rseq_ownership = 1; - if (!rseq_available()) { - rseq_size = 0; - return; - } + + /* Calculate the offset of the rseq area from the thread pointer. */ rseq_offset = (void *)&__rseq_abi - rseq_thread_pointer(); + + /* rseq flags are deprecated, always set to 0. */ rseq_flags = 0; + + /* + * Set the size to 0 until at least one thread registers to mimic the + * libc behavior. + */ + rseq_size = 0; } static __attribute__((destructor)) --- a/tools/testing/selftests/rseq/rseq.h +++ b/tools/testing/selftests/rseq/rseq.h @@ -60,7 +60,14 @@ extern ptrdiff_t rseq_offset; /* - * Size of the registered rseq area. 0 if the registration was + * The rseq ABI is composed of extensible feature fields. The extensions + * are done by appending additional fields at the end of the structure. + * The rseq_size defines the size of the active feature set which can be + * used by the application for the current rseq registration. Features + * starting at offset >= rseq_size are inactive and should not be used. + * + * The rseq_size is the intersection between the available allocation + * size for the rseq area and the feature size supported by the kernel. * unsuccessful. */ extern unsigned int rseq_size;

8 months, 3 weeks

1
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[PATCH 6.12 546/590] selftests/rseq: Fix handling of glibc without rseq support

by Greg Kroah-Hartman

6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> commit 336d02bc4c6bec5c3d933e5d470a94970f830957 upstream. When porting librseq commit: commit c7b45750fa85 ("Adapt to glibc __rseq_size feature detection") from librseq to the kernel selftests, the following line was missed at the end of rseq_init(): rseq_size = get_rseq_kernel_feature_size(); which effectively leaves rseq_size initialized to -1U when glibc does not have rseq support. glibc supports rseq from version 2.35 onwards. In a following librseq commit commit c67d198627c2 ("Only set 'rseq_size' on first thread registration") to mimic the libc behavior, a new approach is taken: don't set the feature size in 'rseq_size' until at least one thread has successfully registered. This allows using 'rseq_size' in fast-paths to test for both registration status and available features. The caveat is that on libc either all threads are registered or none are, while with bare librseq it is the responsability of the user to register all threads using rseq. This combines the changes from the following librseq git commits: commit c7b45750fa85 ("Adapt to glibc __rseq_size feature detection") commit c67d198627c2 ("Only set 'rseq_size' on first thread registration") Fixes: a0cc649353bb ("selftests/rseq: Fix mm_cid test failure") Reported-by: Raghavendra Rao Ananta <rananta(a)google.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: Raghavendra Rao Ananta <rananta(a)google.com> Cc: Shuah Khan <skhan(a)linuxfoundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Boqun Feng <boqun.feng(a)gmail.com> Cc: "Paul E. McKenney" <paulmck(a)kernel.org> Cc: Carlos O'Donell <carlos(a)redhat.com> Cc: Florian Weimer <fweimer(a)redhat.com> Cc: Michael Jeanson <mjeanson(a)efficios.com> Cc: linux-kselftest(a)vger.kernel.org Cc: stable(a)vger.kernel.org Signed-off-by: Shuah Khan <skhan(a)linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- tools/testing/selftests/rseq/rseq.c | 32 +++++++++++++++++++++++++------- tools/testing/selftests/rseq/rseq.h | 9 ++++++++- 2 files changed, 33 insertions(+), 8 deletions(-) --- a/tools/testing/selftests/rseq/rseq.c +++ b/tools/testing/selftests/rseq/rseq.c @@ -61,7 +61,6 @@ unsigned int rseq_size = -1U; unsigned int rseq_flags; static int rseq_ownership; -static int rseq_reg_success; /* At least one rseq registration has succeded. */ /* Allocate a large area for the TLS. */ #define RSEQ_THREAD_AREA_ALLOC_SIZE 1024 @@ -152,14 +151,27 @@ int rseq_register_current_thread(void) } rc = sys_rseq(&__rseq_abi, get_rseq_min_alloc_size(), 0, RSEQ_SIG); if (rc) { - if (RSEQ_READ_ONCE(rseq_reg_success)) { + /* + * After at least one thread has registered successfully + * (rseq_size > 0), the registration of other threads should + * never fail. + */ + if (RSEQ_READ_ONCE(rseq_size) > 0) { /* Incoherent success/failure within process. */ abort(); } return -1; } assert(rseq_current_cpu_raw() >= 0); - RSEQ_WRITE_ONCE(rseq_reg_success, 1); + + /* + * The first thread to register sets the rseq_size to mimic the libc + * behavior. + */ + if (RSEQ_READ_ONCE(rseq_size) == 0) { + RSEQ_WRITE_ONCE(rseq_size, get_rseq_kernel_feature_size()); + } + return 0; } @@ -235,12 +247,18 @@ void rseq_init(void) return; } rseq_ownership = 1; - if (!rseq_available()) { - rseq_size = 0; - return; - } + + /* Calculate the offset of the rseq area from the thread pointer. */ rseq_offset = (void *)&__rseq_abi - rseq_thread_pointer(); + + /* rseq flags are deprecated, always set to 0. */ rseq_flags = 0; + + /* + * Set the size to 0 until at least one thread registers to mimic the + * libc behavior. + */ + rseq_size = 0; } static __attribute__((destructor)) --- a/tools/testing/selftests/rseq/rseq.h +++ b/tools/testing/selftests/rseq/rseq.h @@ -60,7 +60,14 @@ extern ptrdiff_t rseq_offset; /* - * Size of the registered rseq area. 0 if the registration was + * The rseq ABI is composed of extensible feature fields. The extensions + * are done by appending additional fields at the end of the structure. + * The rseq_size defines the size of the active feature set which can be + * used by the application for the current rseq registration. Features + * starting at offset >= rseq_size are inactive and should not be used. + * + * The rseq_size is the intersection between the available allocation + * size for the rseq area and the feature size supported by the kernel. * unsuccessful. */ extern unsigned int rseq_size;

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