On Fri, May 29, 2026 at 11:02 AM Stephen Smalley <[email protected]> wrote: > > On Fri, May 29, 2026 at 9:40 AM Venkat Rao Bagalkote > <[email protected]> wrote: > > > > > > On 29/05/26 12:20 pm, Venkat Rao Bagalkote wrote: > > > Greetings!!! > > > > > > Kernel 7.1.0-rc5-next-20260528 crashes randomly on IBM Power11 > > > hardware. Attached is the config file. > > > > > > **System:** > > > - Hardware: IBM 9080-HEX Power11, pSeries > > > - Broken: 7.1.0-rc5-next-20260528 > > > - Config: 64K pages, Radix MMU > > > > > > > > > **Problem:** > > > Different crash at each reboot. > > > > > > > > > **Example Crash 1:** > > > > > > [ 4.678016] BUG: Unable to handle kernel data access at > > > 0xbffffffefec10628 > > > [ 4.678112] NIP [c008000004e3c74c] > > > xfs_dir2_block_lookup_int+0xd4/0x300 [xfs] > > > [ 4.678281] [c000000005eaf7d0] [c008000004e3c6d4] > > > xfs_dir2_block_lookup_int+0x5c/0x300 [xfs] > > > [ 4.678363] [c000000005eaf850] [c008000004e3d56c] > > > xfs_dir2_block_lookup+0x44/0x1e0 [xfs] > > > > > > > > > **Example Crash 2:** > > > > > > [ 6.327116] BUG: Unable to handle kernel data access at > > > 0x762f736563697695 > > > [ 6.327242] NIP [c00000000073cf34] __refill_obj_stock+0x74/0x2c0 > > > [ 6.327261] [c0000013ffdbfd10] [c0000000007418b8] > > > obj_cgroup_uncharge+0x48/0x70 > > > [ 6.327271] [c0000013ffdbfd50] [c00000000062fffc] > > > free_percpu.part.0+0x12c/0x630 > > > > > > > > > > Git bisect is pointing to 54067bacb49c selinux: hooks: use __getname() > > to allocate path buffer as the first bad commit. > > > > > > # git bisect good > > 54067bacb49caeada82b20b6bd706dca0cb99ffc is the first bad commit > > commit 54067bacb49caeada82b20b6bd706dca0cb99ffc > > Author: Mike Rapoport (Microsoft) <[email protected]> > > Date: Wed May 20 11:18:56 2026 +0300 > > > > selinux: hooks: use __getname() to allocate path buffer > > > > selinux_genfs_get_sid() allocates memory for a path with > > __get_free_page() > > although there is a dedicated helper for allocation of file paths: > > __getname(). > > > > Replace __get_free_page() for allocation of a path buffer with > > __getname(). > > > > Signed-off-by: Mike Rapoport (Microsoft) <[email protected]> > > Signed-off-by: Paul Moore <[email protected]> > > > > security/selinux/hooks.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > # git bisect log > > git bisect start > > # status: waiting for both good and bad commits > > # good: [e7ae89a0c97ce2b68b0983cd01eda67cf373517d] Linux 7.1-rc5 > > git bisect good e7ae89a0c97ce2b68b0983cd01eda67cf373517d > > # status: waiting for bad commit, 1 good commit known > > # bad: [f7af91adc230aa99e23330ecf85bc9badd9780ad] Add linux-next > > specific files for 20260528 > > git bisect bad f7af91adc230aa99e23330ecf85bc9badd9780ad > > # good: [7189ebc81d5e4cb4e03dc4040b07c582b95b09d5] Merge branch > > 'nand/next' of https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git > > git bisect good 7189ebc81d5e4cb4e03dc4040b07c582b95b09d5 > > # skip: [d22aa6f023f3fc275e1f994045a6b347288b2e5a] Merge branch > > 'watchdog-next' of > > https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git > > git bisect skip d22aa6f023f3fc275e1f994045a6b347288b2e5a > > # good: [40d5349aaaae55ec62451bfacc6189cf44ce02cb] iio: adc: ti-ads1298: > > Add parentheses around macro parameter > > git bisect good 40d5349aaaae55ec62451bfacc6189cf44ce02cb > > # good: [6665ab5cf8e74edba571d3d2f31e575f89373dfd] Merge branch > > 'next-integrity' of > > https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity > > git bisect good 6665ab5cf8e74edba571d3d2f31e575f89373dfd > > # bad: [4cc60db652df7ae5d659ec23325c341a52d065e0] Merge branch > > 'driver-core-next' of > > https://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core.git > > git bisect bad 4cc60db652df7ae5d659ec23325c341a52d065e0 > > # bad: [e1d469c38defe7fcb8c6f62a2b7dbf4a103da300] Merge branch 'master' > > of https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git > > git bisect bad e1d469c38defe7fcb8c6f62a2b7dbf4a103da300 > > # good: [4678d11f294de0fd295a265e02955b5d1a4a2684] Merge branch into > > tip/master: 'x86/tdx' > > git bisect good 4678d11f294de0fd295a265e02955b5d1a4a2684 > > # bad: [9397e02d718fc52703d753f489042293cd807dd3] Merge branch 'next' of > > https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git > > git bisect bad 9397e02d718fc52703d753f489042293cd807dd3 > > # good: [c574bdb524095d24169e229b2e3b9318c72e733a] watchdog: > > ziirave_wdt: Use named initializers for struct i2c_device_id > > git bisect good c574bdb524095d24169e229b2e3b9318c72e733a > > # bad: [5568ff6b5e30c7736c24e2096e968c8785c2c245] Merge branch > > 'for-next-tpm' of > > https://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git > > git bisect bad 5568ff6b5e30c7736c24e2096e968c8785c2c245 > > # bad: [23f6b2756d28e76464c7e87850d3d4f6d8c8b365] Merge branch 'next' of > > https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux.git > > git bisect bad 23f6b2756d28e76464c7e87850d3d4f6d8c8b365 > > # good: [ecf41f6218b58c72f1511e395e480f70a9f44889] selinux: reorder > > policydb_index() > > git bisect good ecf41f6218b58c72f1511e395e480f70a9f44889 > > # bad: [54067bacb49caeada82b20b6bd706dca0cb99ffc] selinux: hooks: use > > __getname() to allocate path buffer > > git bisect bad 54067bacb49caeada82b20b6bd706dca0cb99ffc > > # good: [2f0af91353cb64b54cfee5423820d2149039338d] selinux: check for > > simple types > > git bisect good 2f0af91353cb64b54cfee5423820d2149039338d > > # good: [bc3f08d1ef15ebbd32faf0b10cd9699b90b9d30c] selinux: use > > k[mz]alloc() to allocate temporary buffers > > git bisect good bc3f08d1ef15ebbd32faf0b10cd9699b90b9d30c > > # first bad commit: [54067bacb49caeada82b20b6bd706dca0cb99ffc] selinux: > > hooks: use __getname() to allocate path buffer > > > > > > > If you happen to fix this, please add below tag. > > > > > > Reported-by: Venkat Rao Bagalkote <[email protected]> > > IMHO that commit should be reverted: > __getname()/__putname() exist for a different purpose IIUC. > __getname() does a kmalloc(PATH_MAX...), whereas we are then calling > dentry_path_raw(..., PAGE_SIZE) immediately afterward. > This assumes that PATH_MAX == PAGE_SIZE.
Alternatively, I suppose we could just update the dentry_path_raw() call to also pass PATH_MAX, but I don't see why we want to use __getname/__putname() instead of just direct kmalloc/kfree here so the size of the buffer is immediately evident to the reader.
