During kexec reboot, it is possible for a race to occur between device_shutdown() and userspace. This causes accesses to GPU after pm_runtime suspend has already happened. Fix this by calling freeze_processes() before device_shutdown().
Such freezing is already being done if kernel supports KEXEC_JUMP and kexec_image->preserve_context is true. However, doing it if either of these are not true prevents crashes/races. This fixes the following crash during kexec reboot on an ARM64 device with adreno GPU: [ 292.534314] Kernel panic - not syncing: Asynchronous SError Interrupt [ 292.534323] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) [ 292.534326] Call trace: [ 292.534328] dump_backtrace+0x0/0x1d4 [ 292.534337] show_stack+0x20/0x2c [ 292.534342] dump_stack_lvl+0x60/0x78 [ 292.534347] dump_stack+0x18/0x38 [ 292.534352] panic+0x148/0x3b0 [ 292.534357] nmi_panic+0x80/0x94 [ 292.534364] arm64_serror_panic+0x70/0x7c [ 292.534369] do_serror+0x0/0x7c [ 292.534372] do_serror+0x54/0x7c [ 292.534377] el1h_64_error_handler+0x34/0x4c [ 292.534381] el1h_64_error+0x7c/0x80 [ 292.534386] el1_interrupt+0x20/0x58 [ 292.534389] el1h_64_irq_handler+0x18/0x24 [ 292.534395] el1h_64_irq+0x7c/0x80 [ 292.534399] local_daif_inherit+0x10/0x18 [ 292.534405] el1h_64_sync_handler+0x48/0xb4 [ 292.534410] el1h_64_sync+0x7c/0x80 [ 292.534414] a6xx_gmu_set_oob+0xbc/0x1fc [ 292.534422] a6xx_get_timestamp+0x40/0xb4 [ 292.534426] adreno_get_param+0x12c/0x1e0 [ 292.534433] msm_ioctl_get_param+0x64/0x70 [ 292.534440] drm_ioctl_kernel+0xe8/0x158 [ 292.534448] drm_ioctl+0x208/0x320 [ 292.534453] __arm64_sys_ioctl+0x98/0xd0 [ 292.534461] invoke_syscall+0x4c/0x118 Cc: Steven Rostedt <[email protected]> Cc: Ricardo Ribalda <[email protected]> Cc: Ross Zwisler <[email protected]> Cc: Rob Clark <[email protected]> Cc: Linus Torvalds <[email protected]> Tested-by: Ricardo Ribalda <[email protected]> Signed-off-by: Joel Fernandes (Google) <[email protected]> --- kernel/kexec_core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index e2f2574d8b74..6599f485e42d 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1299,6 +1299,12 @@ int kernel_kexec(void) } else #endif { + error = freeze_processes(); + if (error) { + error = -EBUSY; + goto Unlock; + } + kexec_in_progress = true; kernel_restart_prepare("kexec reboot"); migrate_to_reboot_cpu(); -- 2.42.0.582.g8ccd20d70d-goog _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
