From 506ada89629ec7059b96ecfb0dc7d33ece0103ca Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 17:05:56 -0700 Subject: bpf: mark a NULL kfunc argument precise check_kfunc_arg() allows bpf_register_is_null() for nullable arguments w/o marking the underlying scalar register precise. Hence a checkpoint created on such a path would prune against arbitrary scalar value. Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)") Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com Signed-off-by: Alexei Starovoitov --- Documentation/block/error-injection.rst | 59 +++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 Documentation/block/error-injection.rst (limited to 'Documentation/block/error-injection.rst') diff --git a/Documentation/block/error-injection.rst b/Documentation/block/error-injection.rst new file mode 100644 index 000000000..81f31af82 --- /dev/null +++ b/Documentation/block/error-injection.rst @@ -0,0 +1,59 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================ +Configurable Error Injection +============================ + +Overview +-------- + +Configurable error injection allows injecting specific block layer status codes +for sector ranges of a block device. Errors can be injected unconditionally, or +with a given probability. + +To use configurable error injection, CONFIG_BLK_ERROR_INJECTION must be enabled. + +The only interface is the error_injection debugfs file, which is created for +each registered gendisk. Writes to this file are used to create or delete rules +and reads return a list of the current error injection sites. + +Options +------- + +The following options specify the operations: + +=================== ======================================================= +add add a new rule +removeall remove all existing rules +=================== ======================================================= + +The following options specify the details of the rule for the add operation: + +=================== ======================================================= +op= block layer operation this rule applies to. This uses + the XYZ for each REQ_OP_XYZ operation, e.g. READ, WRITE + or DISCARD. Mandatory. +status= Status to return. This uses XYZ for each BLK_STS_XYZ + code, e.g. IOERR or MEDIUM. Mandatory. +start= First block layer sector the rule applies to. + Optional, defaults to 0. +nr_sectors= Number of sectors this rule applies. + Optional, defaults to the remainder of the device. +chance= Only return a failure with a likelihood of 1/chance. + Optional, defaults to 1 (always). +=================== ======================================================= + +Example +------- + +Return BLK_STS_IOERR for one in 10 reads of sector 0 of /dev/nvme0n1: + + $ echo 'add,op=READ,start=0,status=IOERR,chance=10' > /sys/kernel/debug/block/nvme0n1/error_injection + +Return BLK_STS_MEDIUM for every write to /dev/nvme0n1: + + $ echo 'add,op=WRITE,start=0,status=MEDIUM' > /sys/kernel/debug/block/nvme0n1/error_injection + +Remove all rules for /dev/nvme0n1: + + $ echo 'removeall' > /sys/kernel/debug/block/nvme0n1/error_injection -- cgit v1.3.1